Computer Mediated Communications (CMC)

Computer Mediated Communication Wikibook ITEC30011

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Contents Articles Computer-mediated communication

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Email

4

Instant messaging

19

Social networking service

28

Opportunity cost

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Acceptable use policy

43

References Article Sources and Contributors

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Image Sources, Licenses and Contributors

49

Article Licenses License

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Computer-mediated communication

Computer-mediated communication Computer-mediated communication (CMC) is defined as any communicative transaction that occurs through the use of two or more networked computers.[1] While the term has traditionally referred to those communications that occur via computer-mediated formats (e.g., instant messages, e-mails, chat rooms), it has also been applied to other forms of text-based interaction such as text messaging.[2] Research on CMC focuses largely on the social effects of different computer-supported communication technologies. Many recent studies involve Internet-based social networking supported by social software.

Scope of the field Scholars from a variety of fields study phenomena that can be described under the umbrella term of CMC (see also Internet studies). For example, many take a sociopsychological approach to CMC by examining how humans use "computers" (or digital media) to manage interpersonal interaction, form impressions and form and maintain relationships.[3] [4] These studies have often focused on the differences between online and offline interactions, though contemporary research is moving towards the view that CMC should be studied as embedded in everyday life .[5] Another branch of CMC research examines the use of paralinguistic features such as emoticons, pragmatic rules such as turn-taking[6] and the sequential analysis and organization of talk,[7] [8] and the various sociolects, styles, registers or sets of terminology specific to these environments (see Leet). The study of language in these contexts is typically based on text-based forms of CMC, and is sometimes referred to as "computer-mediated discourse analysis".[9] The way humans communicate in professional, social, and educational settings varies widely, depending upon not only the environment but also the method of communication in which the communication occurs, which in this case is through computers or other information and computer technologies (ICTs). The study of communication to achieve collaboration—common work products—is termed computer-supported collaboration and includes only some of the concerns of other forms of CMC research.

Popular forms of CMC include e-mail, video, audio or text chat (text conferencing including "instant messaging"), bulletin boards, list-servs and MMOs.[10] These settings are changing rapidly with the development of new technologies. Weblogs (blogs) have also become popular, and the exchange of RSS data has better enabled users to each "become their own publisher".

Characteristics Communication occurring within a computer-mediated format has an effect on many different aspects of an interaction. Some of these that have received attention in the scholarly literature include impression formation, deception, group dynamics, disinhibition and especially relationship formation.

CMC is examined and compared to other communication media through a number of aspects thought to be universal to all forms of communication, including (but not limited to) synchronicity, persistence or "recordability", and anonymity. The association of these aspects with different forms of communication varies widely. For example, instant messaging is intrinsically synchronous but not persistent, since one loses all the content when one closes the dialog box unless one has a message log set up or has manually copy-pasted the conversation. E-mail and message boards, on the other hand, are low in synchronicity since response time varies, but high in persistence since messages sent and received are saved. Properties that separate CMC from other media also include transience, its multimodal nature, and its relative lack of governing codes of conduct.[11] CMC is able to overcome physical and social limitations of other forms of communication and therefore allow the interaction of people who are not physically sharing the same space.

1

Computer-mediated communication Anonymity and in part privacy and security depends more on the context and particular program being used or web page being visited. However, most researchers in the field acknowledge the importance of considering the psychological and social implications of these factors alongside the technical "limitations".

Types CMC can be divided into synchronous and asynchronous modes. In synchronous communications all participants are online at the same time (e.g. IRC), while asynchronous communications occurs with time constraints. (e.g e mail)

Language learning CMC is widely discussed in language learning because CMC provides opportunities for language learners to practice their language.[12] For example, Warschauer[13] conducted several case studies on using email or discussion boards in different language classes. Warschauer[14] claimed that information and communications technology “bridge the historic divide between speech … and writing”. Thus, considerable concern has arisen over the reading and writing research in L2 due to the booming of Internet.

References [1] McQuail, Denis. (2005). Mcquail's Mass Communication Theory. 5th ed. London: SAGE Publications.

[2] Thurlow, C., Lengel, L. & Tomic, A. (2004). Computer mediated communication: Social interaction and the internet. London: Sage.

[3] Walther, J. B. (1996). Computer-mediated communication: Impersonal, interpersonal, and hyperpersonal interaction. Communication Research, 23, 3-43.

[4] Walther, J. B., & Burgoon, J. K. (1992). Relational communication in computer-mediated interaction. Human Communication Research, 19, 50-88.

[5] Haythornthwaite, C. and Wellman, B. (2002). The Internet in everyday life: An introduction. In B. Wellman and C. Haythornthwaite (Eds.), The Internet in Everyday Life (pp. 3-41). Oxford: Blackwell.

[6] Garcia, A. C., & Jacobs, J. B. (1999). The eyes of the beholder: Understanding the turn-taking system in quasi-synchronous computer-mediated communication. Research on Language & Social Interaction, 32, 337-367.

[7] Herring, S. (1999). Interactional coherence in CMC. Journal of Computer-Mediated Communication, 4(4). http:/ / jcmc. indiana. edu/ vol4/ issue4/ herring. html [8] Markman, K. M. (2006). Computer-mediated conversation: The organization of talk in chat-based virtual team meetings. Dissertation Abstracts International, 67 (12A), 4388. (UMI No. 3244348) [9] Herring, S. C. (2004). Computer-mediated discourse analysis: An approach to researching online behavior. In: S. A. Barab, R. Kling, and J. H. Gray (Eds.), Designing for Virtual Communities in the Service of Learning (pp. 338-376). New York: Cambridge University Press.

[10] Bishop, J. (2009). Enhancing the understanding of genres of web-based communities: The role of the ecological cognition framework.

International Journal of Web-Based Communities, 5(1), 4-17. Available online (http:/ / crocels. com/ index. php?q=node/ 6) [11] McQuail, Denis. (2005). Mcquail's Mass Communication Theory. 5th ed. London: SAGE Publications.

[12] Abrams, Z. (2006). From Theory to Practice: Intracultural CMC in the L2 Classroom. book chapter, forthcoming in Ducate, Lara & Nike Arnold (Eds.) Calling on CALL: From Theory and Research to New Directions in Foreign Language Teaching.

[13] Warschauer, M. (1998). Electronic literacies: Language, culture and power in online education. Mahwah, NJ: Lawrence Erlbaum Associates.

[14] Warschauer, M. (2006). Laptops and literacy: learning in the wireless classroom: Teachers College, Columbia University.

Further reading Ahern, T.C., Peck, K., & Laycock, M. (1992). The effects of teacher discourse in computer-mediated discussion.

Journal of Educational Computing Research, 8(3), 291-309.

Angeli, C., Valanides, N., & Bonk, C.J. (2003). Communication in a web-based conferencing system: The quality of computer-mediated interactions. British Journal of Educational Technology, 34(1), 31-43.

Bannan-Ritland, B. (2002). Computer-mediated communication, elearning, and interactivity: A review of the research. Quarterly Review of Distance Education, 3(2), 161-180.

Christopher, M.M., Thomas, J.A., and Tallent-Runnels, M.K. (2004). Raising the Bar: Encouraging high level thinking in online discussion forums. Roeper Review, 26(3), 166-171.

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Computer-mediated communication Cooper, M.M., & Selfe, C.L. (1990). Computer conferences and learning: Authority, resistance, and internally persuasive discourse. College English, 52(8), 847-869.

Forman, E.A. (2000). Knowledge building in discourse communities. Human Development, 43(6), 364-368.

Gabriel, M.A. (2004). Learning together: Exploring group interactions online. Journal of Distance Education, 19(1), 54-72.

Gilbert, K.G., & Dabbagh, N. (2005). How to structure online discussions for meaningful discourse: a case study.

British Journal of Educational Technology, 36(1), 5-18.

Gunawardena, C.H., Nolla, A.C., Wilson, P.L., Lopez-Isias, Jr. et al. (2001). A cross-cultural study of group process and development in online conferences. Distance Education, 22(1), 85-122.

Hara, N., Bonk, C.J., & Angeli, C. (2000). Content analysis of online discussion in an applied educational psychology course. Instructional Science, 28, 115-152.

Hewitt, J. (2001). Beyond threaded discourse. International Journal of Educational Telecommunications, 7(3), 207-221.

Hewitt, J. (2003). How habitual online practices affect the development of asynchronous discussion threads. Journal of Educational Computing Research, 28(1), 31-45.

Javela, S., Bonk, C.J., & Sirpalethti, S.L. (1999). A theoretical analysis of social interactions in computer-based learning environments: Evidence for reciprocal understandings. Journal of Educational Computing Research, 21(3), 363-388.

Jones, G., & Schieffelin, B. (2009). Enquoting Voices, Accomplishing Talk: Uses of Be+Like in Instant Messaging.

Language & Communication, 29(1), 77-113.

Jones, G., & Schieffelin, B. (2009). Talking Text and Talking Back: "My BFF Jill" from Boob Tube to YouTube.

Journal of Computer-Mediated Communication, 14(4), 1050 - 1079.

Kalman, Y. M. and Rafaeli, S. (2007-05-23). Modulating Synchronicity in Computer-Mediated Communication.

Paper presented at the annual meeting of the International Communication Association, TBA, San Francisco, CA Online <APPLICATION/PDF>. 2010-01-24 from http://www.allacademic.com/meta/p170694_index.html Kirk, J.J., & Orr, R.L. (2003). A primer on the effective use of threaded discussion forums. ERIC document.

Lapadat, J.C. (2003). Teachers in an online seminar talking about talk: Classroom discourse and school change.

Language and Education, 17(1), 21-41.

Leinonen, P., Jarvela, S., & Lipponen, L. (2003). Individual students’ interpretations of their contribution to the computer-mediated discussions. Journal of Interactive Learning Research, 14(1), 99-122.

Lin, L. (2008). An online learning model to facilitate learners’ rights to education. Journal of Asynchronous Learning Networks (JALN), 12(1), pp. 127–143. [Special issue distributed by Sloan-C JALN in collaboration with five other international journals: http://www.distanceandaccesstoeducation.org/] Lin, L., Cranton, P. & Bridglall, B. (2005). Psychological type and asynchronous written dialogue in adult learning.

Teachers College Record, 107(8), 1788-1813.

MackNnight, C.B. (2000). Teaching critical thinking through online discussions. Educause Quarterly, 4, 38-41.

Poole, D.M. (2000). Student participation in a discussion-oriented online course: A case study. Journal of Research on Computing in Education, 33(2), 162-176.

Schrire, S. (2003). A model for evaluating the process of learning in asynchronous computer conferencing. Journal of Instructional Delivery Systems, 17(1), 6-12.

Vonderwell, S. (2002). An examination of asynchronous communication experiences and perspectives of students in an online course: A case study. The Internet and Higher Education, 6, 77-90.

3

Computer-mediated communication Wade, S.E., & Fauske, J.R. (2004). Dialogue online: Prospective teachers’ discourse strategies in computer-mediated discussions. Reading Research Quarterly, 39(2), 134-160.

Wu, D., & Hiltz, S.R. (2004). Predicting learning from asynchronous online discussions. Journal of Asynchronous Learning Networks, 8(2), 139-152.

Email Electronic mail, commonly called email or e-mail, is a method of exchanging digital messages from an author to one or more recipients.

Modern email operates across the Internet or other computer networks. Some early email systems required that the author and the recipient both be online at the same time, a la instant messaging. Today's email systems are based on a store-and-forward model. Email servers accept, forward, deliver and store messages. Neither the users nor their computers are required to be online simultaneously; they need connect only briefly, typically to an email server, for as long as it takes to send or receive messages.

An email message consists of three components, the message envelope, the The at sign, a part of every SMTP email [1] address message header, and the message body. The message header contains control information, including, minimally, an originator's email address and one or more recipient addresses. Usually descriptive information is also added, such as a subject header field and a message submission date/time stamp.

Originally a text-only (7-bit ASCII and others) communications medium, email was extended to carry multi-media content attachments, a process standardized in RFC 2045 through 2049. Collectively, these RFCs have come to be called Multipurpose Internet Mail Extensions (MIME).

The history of modern, global Internet email services reaches back to the early ARPANET. Standards for encoding email messages were proposed as early as 1973 (RFC 561). Conversion from ARPANET to the Internet in the early 1980s produced the core of the current services. An email sent in the early 1970s looks quite similar to a basic text message sent on the Internet today.

Network-based email was initially exchanged on the ARPANET in extensions to the File Transfer Protocol (FTP), but is now carried by the Simple Mail Transfer Protocol (SMTP), first published as Internet standard 10 (RFC 821) in 1982. In the process of transporting email messages between systems, SMTP communicates delivery parameters using a message envelope separate from the message (header and body) itself.

Spelling There are several spelling options that occasionally prove cause for surprisingly vehement disagreement.[2] [3] • email is the form required by IETF Requests for Comment and working groups[4] and increasingly by style guides.[5] [6] [7] This spelling also appears in most dictionaries.[8] [9] [10] [11] [12] [13] • e-mail is a form previously recommended by some prominent journalistic and technical style guides. According to Corpus of Contemporary American English data, this form appears most frequently in edited, published American English writing.[14] • mail was the form used in the original RFC. The service is referred to as mail and a single piece of electronic mail is called a message.[15] [16] [17] • eMail, capitalizing only the letter M, was common among ARPANET users and the early developers of Unix, CMS, AppleLink, eWorld, AOL, GEnie, and Hotmail.

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Email • EMail is a traditional form that has been used in RFCs for the "Author's Address",[16] [17] and is expressly required "...for historical reasons...".[18] • E-mail, capitalizing the initial letter E in the same way as A-bomb, H-bomb, X-ray, T-shirt, and similar shortenings.[19]

Origin Electronic mail predates the inception of the Internet, and was in fact a crucial tool in creating it.[20] MIT first demonstrated the Compatible Time-Sharing System (CTSS) in 1961.[21] It allowed multiple users to log into the IBM 7094[22] from remote dial-up terminals, and to store files online on disk. This new ability encouraged users to share information in new ways. Email started in 1965 as a way for multiple users of a time-sharing mainframe computer to communicate. Among the first systems to have such a facility were SDC's Q32 and MIT's CTSS.

Host-based mail systems The original email systems allowed communication only between users who logged into the same host or "mainframe". This could be hundreds or even thousands of users within an organization. Examples include MIT's 1965 CTSS MAIL,[23] Larry Breed's 1972 APL Mailbox (which was used by the 1976 Carter/Mondale presidential campaign),[24] [25] the original 1972 Unix mail program,[26] [27] IBM's 1981 PROFS, and Digital Equipment Corporation's 1982 ALL-IN-1,.[28]

Homogeneous email networks and LAN-based mail systems Many early peer-to-peer email networking only worked among computers running the same OS or program.

Examples include: • By 1966 or earlier, it is possible that the SAGE system had a limited form of email • 1978's uucp[29] and 1980's Usenet provided Unix-to-Unix copying of email, files, and shared fora over dialup modems or leased lines • BITNET in 1981 allowed IBM mainframes to communicate email over leased lines.

• FidoNet's 1984 application software for IBM PC's running DOS transferred email and shared bulletin board postings by dialup modem In the early 1980s, networked personal computers on LANs became increasingly important. Server-based systems similar to the earlier mainframe systems were developed. Again these systems initially allowed communication only between users logged into the same server infrastructure. Eventually these systems could also be linked between different organizations, as long as they ran the same email system and proprietary protocol.

Examples include cc:Mail, Lantastic, WordPerfect Office, Microsoft Mail, Banyan VINES and Lotus Notes - with various vendors supplying gateway software to link these incompatible systems.

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Email

Attempts at interoperability Early interoperability among independent systems included: • ARPANET, the forerunner of today's Internet, defined the first protocols for dissimilar computers to exchange email • uucp implementations for non-Unix systems were used as an open "glue" between differing mail systems, primarily over dialup telephones • CSNet used dial-up telephone access to link additional sites to the ARPANET and then Internet Later efforts at interoperability standardization included: • Novell briefly championed the open MHS protocol but abandoned it after purchasing the non-MHS WordPerfect Office (renamed Groupwise) • The Coloured Book protocols on UK academic networks until 1992 • X.400 in the 1980s and early 1990s was promoted by major vendors and mandated for government use under GOSIP but abandoned by all but a few — in favor of Internet SMTP by the mid-1990s.

From SNDMSG to MSG In the early 1970s, Ray Tomlinson updated an existing utility called SNDMSG so that it could copy messages (as files) over the network. Lawrence Roberts, the project manager for the ARPANET development, took the idea of READMAIL, which dumped all "recent" messages onto the user's terminal, and wrote a program for TENEX in TECO macros called RD which permitted accessing individual messages.[30] Barry Wessler then updated RD and called it NRD. Marty Yonke combined rewrote NRD to include reading, access to SNMSG for sending, and a help system, and called the utility WRD which was later known as BANANARD. John Vittal then updated this version to include message forwarding and an Answer command that automatically created a reply message with the correct address(es). This was the first email "reply" command; the system was called MSG. With inclusion of these features, MSG is considered to be the first integrated modern email program, from which many other applications have descended.[30]

The rise of ARPANET mail The ARPANET computer network made a large contribution to the development of email. There is one report that indicates experimental inter-system email transfers began shortly after its creation in 1969.[23] Ray Tomlinson is generally credited as having sent the first email across a network, initiating the use of the "@" sign to separate the names of the user and the user's machine in 1971, when he sent a message from one Digital Equipment Corporation DEC-10 computer to another DEC-10. The two machines were placed next to each other.[31] [32] Tomlinson's work was quickly adopted across the ARPANET, which significantly increased the popularity of email. For many years, email was the killer app of the ARPANET and then the Internet.

Most other networks had their own email protocols and address formats; as the influence of the ARPANET and later the Internet grew, central sites often hosted email gateways that passed mail between the Internet and these other networks. Internet email addressing is still complicated by the need to handle mail destined for these older networks.

Some well-known examples of these were UUCP (mostly Unix computers), BITNET (mostly IBM and VAX mainframes at universities), FidoNet (personal computers), DECNET (various networks) and CSNET a forerunner of NSFNet. An example of an Internet email address that routed mail to a user at a UUCP host: hubhost!middlehost!edgehost!user@uucpgateway.somedomain.example.com

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Email This was necessary because in early years UUCP computers did not maintain (or consult servers for) information about the location of all hosts they exchanged mail with, but rather only knew how to communicate with a few network neighbors; email messages (and other data such as Usenet News) were passed along in a chain among hosts who had explicitly agreed to share data with each other.

Operation overview The diagram to the right shows a typical sequence of events[33] that takes place when Alice composes a message using her mail user agent (MUA). She enters the email address of her correspondent, and hits the "send" button.

1. Her MUA formats the message in email format and uses the Submission Protocol (a profile of the Simple Mail Transfer Protocol (SMTP), see RFC 4409) to send the message to the local mail submission agent (MSA), in this case smtp.a.org, run by Alice's internet service provider (ISP).

2. The MSA looks at the destination address provided in the SMTP protocol (not from the message header), in this case bob@b.org. An Internet email address is a string of the form localpart@exampledomain. The part before the @ sign is the local part of the address, often the username of the recipient, and the part after the @ sign is a domain name or a fully qualified domain name. The MSA resolves a domain name to determine the fully qualified domain name of the mail exchange server in the Domain Name System (DNS).

3. The DNS server for the b.org domain, ns.b.org, responds with any MX records listing the mail exchange servers for that domain, in this case mx.b.org, a message transfer agent (MTA) server run by Bob's ISP. 4. smtp.a.org sends the message to mx.b.org using SMTP. This server may need to forward the message to other MTAs before the message reaches the final message delivery agent (MDA).

1. The MDA delivers it to the mailbox of the user bob.

2. Bob presses the "get mail" button in his MUA, which picks up the message using either the Post Office Protocol (POP3) or the Internet Message Access Protocol (IMAP4).

That sequence of events applies to the majority of email users. However, there are many alternative possibilities and complications to the email system: â&#x20AC;˘ Alice or Bob may use a client connected to a corporate email system, such as IBM Lotus Notes or Microsoft Exchange. These systems often have their own internal email format and their clients typically communicate with the email server using a vendor-specific, proprietary protocol. The server sends or receives email via the Internet

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Email

• • • • •

8 through the product's Internet mail gateway which also does any necessary reformatting. If Alice and Bob work for the same company, the entire transaction may happen completely within a single corporate email system.

Alice may not have a MUA on her computer but instead may connect to a webmail service.

Alice's computer may run its own MTA, so avoiding the transfer at step 1.

Bob may pick up his email in many ways, for example logging into mx.b.org and reading it directly, or by using a webmail service.

Domains usually have several mail exchange servers so that they can continue to accept mail when the main mail exchange server is not available.

Email messages are not secure if email encryption is not used correctly.

Many MTAs used to accept messages for any recipient on the Internet and do their best to deliver them. Such MTAs are called open mail relays. This was very important in the early days of the Internet when network connections were unreliable. If an MTA couldn't reach the destination, it could at least deliver it to a relay closer to the destination.

The relay stood a better chance of delivering the message at a later time. However, this mechanism proved to be exploitable by people sending unsolicited bulk email and as a consequence very few modern MTAs are open mail relays, and many MTAs don't accept messages from open mail relays because such messages are very likely to be spam.

Message format The Internet email message format is defined in RFC 5322, with multi-media content attachments being defined in RFC 2045 through RFC 2049, collectively called Multipurpose Internet Mail Extensions or MIME. Prior to the introduction of RFC 2822 in 2001, the format described by RFC 822 was the standard for Internet email for nearly 20 years. RFC 822 was published in 1982 and based on the earlier RFC 733 for the ARPANET (see).[34] Internet email messages consist of two major sections: • Header — Structured into fields such as From, To, CC, Subject, Date, and other information about the email.

• Body — The basic content, as unstructured text; sometimes containing a signature block at the end. This is exactly the same as the body of a regular letter.

The header is separated from the body by a blank line.

Message header Each message has exactly one header, which is structured into fields. Each field has a name and a value. RFC 5322 specifies the precise syntax.

Informally, each line of text in the header that begins with a printable character begins a separate field. The field name starts in the first character of the line and ends before the separator character ":". The separator is then followed by the field value (the "body" of the field). The value is continued onto subsequent lines if those lines have a space or tab as their first character. Field names and values are restricted to 7-bit ASCII characters. Non-ASCII values may be represented using MIME encoded words.

Email Header fields The message header must include at least the following fields[35] : • From: The email address, and optionally the name of the author(s). In many email clients not changeable except through changing account settings.

• Date: The local time and date when the message was written. Like the From: field, many email clients fill this in automatically when sending. The recipient's client may then display the time in the format and time zone local to him/her.

The message header should include at least the following fields[36] : • Message-ID: Also an automatically generated field; used to prevent multiple delivery and for reference in In-Reply-To: (see below).

• In-Reply-To: Message-ID of the message that this is a reply to. Used to link related messages together. This field only applies for reply messages.

RFC 3864 describes registration procedures for message header fields at the IANA; it provides for permanent [37] and provisional [38] message header field names, including also fields defined for MIME, netnews, and http, and referencing relevant RFCs. Common header fields for email include: • To: The email address(es), and optionally name(s) of the message's recipient(s). Indicates primary recipients (multiple allowed), for secondary recipients see Cc: and Bcc: below.

• Subject: A brief summary of the topic of the message. Certain abbreviations are commonly used in the subject, including "RE:" and "FW:".

• Bcc: Blind Carbon Copy; addresses added to the SMTP delivery list but not (usually) listed in the message data, remaining invisible to other recipients.

• Cc: Carbon copy; Many email clients will mark email in your inbox differently depending on whether you are in the To: or Cc: list.

• Content-Type: Information about how the message is to be displayed, usually a MIME type.

• Precedence: commonly with values "bulk", "junk", or "list"; used to indicate that automated "vacation" or "out of office" responses should not be returned for this mail, e.g. to prevent vacation notices from being sent to all other subscribers of a mailinglist. Sendmail uses this header to affect prioritization of queued email, with "Precedence: special-delivery" messages delivered sooner. With modern high-bandwidth networks delivery priority is less of an issue than it once was. Microsoft Exchange respects a fine-grained automatic response suppression mechanism, the X-Auto-Response-Suppress header.[39] • Received: Tracking information generated by mail servers that have previously handled a message, in reverse order (last handler first).

• References: Message-ID of the message that this is a reply to, and the message-id of the message the previous was reply a reply to, etc.

• Reply-To: Address that should be used to reply to the message.

• Sender: Address of the actual sender acting on behalf of the author listed in the From: field (secretary, list manager, etc.).

Note that the To: field is not necessarily related to the addresses to which the message is delivered. The actual delivery list is supplied separately to the transport protocol, SMTP, which may or may not originally have been extracted from the header content. The "To:" field is similar to the addressing at the top of a conventional letter which is delivered according to the address on the outer envelope. Also note that the "From:" field does not have to be the real sender of the email message. One reason is that it is very easy to fake the "From:" field and let a message seem to be from any mail address. It is possible to digitally sign email, which is much harder to fake, but such signatures require extra programming and often external programs to verify. Some ISPs do not relay email claiming to come from a domain not hosted by them, but very few (if any) check to make sure that the person or even email address named in the "From:" field is the one associated with the connection. Some ISPs apply email authentication

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Email systems to email being sent through their MTA to allow other MTAs to detect forged spam that might appear to come from them.

Recently the IETF EAI working group has defined some experimental extensions to allow Unicode characters to be used within the header. In particular, this allows email addresses to use non-ASCII characters. Such characters must only be used by servers that support these extensions.

Message body Content encoding Email was originally designed for 7-bit ASCII.[40] Much email software is 8-bit clean but must assume it will communicate with 7-bit servers and mail readers. The MIME standard introduced character set specifiers and two content transfer encodings to enable transmission of non-ASCII data: quoted printable for mostly 7 bit content with a few characters outside that range and base64 for arbitrary binary data. The 8BITMIME and BINARY extensions were introduced to allow transmission of mail without the need for these encodings, but many mail transport agents still do not support them fully. In some countries, several encoding schemes coexist; as the result, by default, the message in a non-Latin alphabet language appears in non-readable form (the only exception is coincidence, when the sender and receiver use the same encoding scheme). Therefore, for international character sets, Unicode is growing in popularity.

Plain text and HTML Most modern graphic email clients allow the use of either plain text or HTML for the message body at the option of the user. HTML email messages often include an automatically generated plain text copy as well, for compatibility reasons.

Advantages of HTML include the ability to include in-line links and images, set apart previous messages in block quotes, wrap naturally on any display, use emphasis such as underlines and italics, and change font styles.

Disadvantages include the increased size of the email, privacy concerns about web bugs, abuse of HTML email as a vector for phishing attacks and the spread of malicious software.[41] Some web based Mailing lists recommend that all posts be made in plain-text, with 72 or 80 characters per line[42] [43] for all the above reasons, but also because they have a significant number of readers using text-based email clients such as Mutt.

Some Microsoft email clients allow rich formatting using RTF, but unless the recipient is guaranteed to have a compatible email client this should be avoided.[44] In order to ensure that HTML sent in an email is rendered properly by the recipient's client software, an additional header must be specified when sending: "Content-type: text/html". Most email programs send this header automatically.

Servers and client applications Messages are exchanged between hosts using the Simple Mail Transfer Protocol with software programs called mail transfer agents. Users can retrieve their messages from servers using standard protocols such as POP or IMAP, or, as is more likely in a large corporate environment, with a proprietary protocol specific to Novell Groupwise, Lotus Notes or Microsoft Exchange Servers. Webmail interfaces allow users to access their mail with any standard web browser, from any computer, rather than relying on an email client.

Mail can be stored on the client, on the server side, or in both places. Standard formats for mailboxes include Maildir and mbox. Several prominent email clients use their own proprietary format and require conversion software to transfer email between them.

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Email

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Accepting a message obliges an MTA to deliver it,[45] and when a message cannot be delivered, that MTA must send a bounce message back to the sender, indicating the problem.

Filename extensions Upon reception of email messages, email client applications save message in operating system files in the file-system. Some clients save individual messages as separate files, while others use various database formats, often proprietary, for collective storage. A historical standard of storage is the mbox format. The specific format used is often indicated by special filename extensions: eml Used by many email clients including Microsoft Outlook Express, Windows Mail and Mozilla Thunderbird.[46] The files are plain text in MIME format, containing the email header as well as the message contents and attachments in one or more of several formats. emlx Used by Apple Mail. msg Used by Microsoft Office Outlook and OfficeLogic Groupware. mbx Used by Opera Mail, KMail, and Apple Mail based on the mbox format.

Some applications (like Apple Mail) leave attachments encoded in messages for searching while also saving separate copies of the attachments. Others separate attachments from messages and save them in a specific directory.

URI scheme mailto: The URI scheme, as registered with the IANA, defines the mailto: scheme for SMTP email addresses. Though its use is not strictly defined, URLs of this form are intended to be used to open the new message window of the user's mail client when the URL is activated, with the address as defined by the URL in the To: field.[47]

Use In society There are numerous ways in which people have changed the way they communicate in the last 50 years; email is certainly one of them. Traditionally, social interaction in the local community was the basis for communication â&#x20AC;&#x201C; face to face. Yet, today face-to-face meetings are no longer the primary way to communicate as one can use a landline telephone, mobile phones, fax services, or any number of the computer mediated communications such as email.

Flaming Flaming occurs when a person sends a message with angry or antagonistic content. Flaming is assumed to be more common today because of the ease and impersonality of email communications: confrontations in person or via telephone require direct interaction, where social norms encourage civility, whereas typing a message to another person is an indirect interaction, so civility may be forgotten. Flaming is generally looked down upon by Internet communities as it is considered rude and non-productive.

Email Email bankruptcy Also known as "email fatigue", email bankruptcy is when a user ignores a large number of email messages after falling behind in reading and answering them. The reason for falling behind is often due to information overload and a general sense there is so much information that it is not possible to read it all. As a solution, people occasionally send a boilerplate message explaining that the email inbox is being cleared out. Harvard University law professor Lawrence Lessig is credited with coining this term, but he may only have popularized it.[48]

In business Email was widely accepted by the business community as the first broad electronic communication medium and was the first ‘e-revolution’ in business communication. Email is very simple to understand and like postal mail, email solves two basic problems of communication: logistics and synchronization (see below).

LAN based email is also an emerging form of usage for business. It not only allows the business user to download mail when offline, it also provides the small business user to have multiple users email ID's with just one email connection.

Pros • The problem of logistics: Much of the business world relies upon communications between people who are not physically in the same building, area or even country; setting up and attending an in-person meeting, telephone call, or conference call can be inconvenient, time-consuming, and costly. Email provides a way to exchange information between two or more people with no set-up costs and that is generally far less expensive than physical meetings or phone calls.

• The problem of synchronisation: With real time communication by meetings or phone calls, participants have to work on the same schedule, and each participant must spend the same amount of time in the meeting or call.

Email allows asynchrony: each participant may control their schedule independently.

Cons Most business workers today spend from one to two hours of their working day on email: reading, ordering, sorting, ‘re-contextualizing’ fragmented information, and writing email.[49] The use of email is increasing due to increasing levels of globalisation—labour division and outsourcing amongst other things. Email can lead to some well-known problems: • Loss of context: which means that the context is lost forever; there is no way to get the text back. Information in context (as in a newspaper) is much easier and faster to understand than unedited and sometimes unrelated fragments of information. Communicating in context can only be achieved when both parties have a full understanding of the context and issue in question.

• Information overload: Email is a push technology—the sender controls who receives the information. Convenient availability of mailing lists and use of "copy all" can lead to people receiving unwanted or irrelevant information of no use to them.

• Inconsistency: Email can duplicate information. This can be a problem when a large team is working on documents and information while not in constant contact with the other members of their team.

• Liability. Statements made in an email can be deemed legally binding and be used against a party in a Court of law.[50] Despite these disadvantages, email has become the most widely used medium of communication within the business world. In fact, a 2010 study on workplace communication [51], found that 83% of U.S. knowledge workers felt that email was critical to their success and productivity at work.[52]

12

Email

Problems Attachment size limitation Email messages may have one or more attachments. Attachments serve the purpose of delivering binary or text files of unspecified size. In principle there is no technical intrinsic restriction in the SMTP protocol limiting the size or number of attachments. In practice, however, email service providers implement various limitations on the permissible size of files or the size of an entire message.

Furthermore, due to technical reasons, often a small attachment can increase in size when sent,[53] which can be confusing to senders when trying to assess whether they can or cannot send a file by email, and this can result in their message being rejected.

As larger and larger file sizes are being created and traded, many users are either forced to upload and download their files using an FTP server, or more popularly, use online file sharing facilities or services, usually over web-friendly HTTP, in order to send and receive them.

Information overload A December 2007 New York Times blog post described information overload as "a $650 Billion Drag on the Economy",[54] and the New York Times reported in April 2008 that "E-MAIL has become the bane of some peopleâ&#x20AC;&#x2122;s professional lives" due to information overload, yet "none of the current wave of high-profile Internet start-ups focused on e-mail really eliminates the problem of e-mail overload because none helps us prepare replies".[55] GigaOm posted a similar article in September 2010, highlighting research [56] that found 57% of knowledge workers were overwhelmed by the volume of email they received.[52] Technology investors reflect similar concerns.[57]

Spamming and computer viruses The usefulness of email is being threatened by four phenomena: email bombardment, spamming, phishing, and email worms.

Spamming is unsolicited commercial (or bulk) email. Because of the very low cost of sending email, spammers can send hundreds of millions of email messages each day over an inexpensive Internet connection. Hundreds of active spammers sending this volume of mail results in information overload for many computer users who receive voluminous unsolicited email each day.[58] [59] Email worms use email as a way of replicating themselves into vulnerable computers. Although the first email worm affected UNIX computers, the problem is most common today on the more popular Microsoft Windows operating system.

The combination of spam and worm programs results in users receiving a constant drizzle of junk email, which reduces the usefulness of email as a practical tool.

A number of anti-spam techniques mitigate the impact of spam. In the United States, U.S. Congress has also passed a law, the Can Spam Act of 2003, attempting to regulate such email. Australia also has very strict spam laws restricting the sending of spam from an Australian ISP,[60] but its impact has been minimal since most spam comes from regimes that seem reluctant to regulate the sending of spam.

13

Email

Email spoofing Email spoofing occurs when the header information of an email is altered to make the message appear to come from a known or trusted source. It is often used as a ruse to collect personal information.

Email bombing Email bombing is the intentional sending of large volumes of messages to a target address. The overloading of the target email address can render it unusable and can even cause the mail server to crash.

Privacy concerns Today it can be important to distinguish between Internet and internal email systems. Internet email may travel and be stored on networks and computers without the sender's or the recipient's control. During the transit time it is possible that third parties read or even modify the content. Internal mail systems, in which the information never leaves the organizational network, may be more secure, although information technology personnel and others whose function may involve monitoring or managing may be accessing the email of other employees.

Email privacy, without some security precautions, can be compromised because: • email messages are generally not encrypted.

• email messages have to go through intermediate computers before reaching their destination, meaning it is relatively easy for others to intercept and read messages.

• many Internet Service Providers (ISP) store copies of email messages on their mail servers before they are delivered. The backups of these can remain for up to several months on their server, despite deletion from the mailbox.

• the "Received:"-fields and other information in the email can often identify the sender, preventing anonymous communication.

There are cryptography applications that can serve as a remedy to one or more of the above. For example, Virtual Private Networks or the Tor anonymity network can be used to encrypt traffic from the user machine to a safer network while GPG, PGP, SMEmail,[61] or S/MIME can be used for end-to-end message encryption, and SMTP STARTTLS or SMTP over Transport Layer Security/Secure Sockets Layer can be used to encrypt communications for a single mail hop between the SMTP client and the SMTP server.

Additionally, many mail user agents do not protect logins and passwords, making them easy to intercept by an attacker. Encrypted authentication schemes such as SASL prevent this.

Finally, attached files share many of the same hazards as those found in peer-to-peer filesharing. Attached files may contain trojans or viruses.

Tracking of sent mail The original SMTP mail service provides limited mechanisms for tracking a transmitted message, and none for verifying that it has been delivered or read. It requires that each mail server must either deliver it onward or return a failure notice (bounce message), but both software bugs and system failures can cause messages to be lost. To remedy this, the IETF introduced Delivery Status Notifications (delivery receipts) and Message Disposition Notifications (return receipts); however, these are not universally deployed in production. (A complete Message Tracking mechanism was also defined, but it never gained traction; see RFCs 3885 through 3888.)

Many ISPs now deliberately disable non-delivery reports (NDRs) and delivery receipts due to the activities of spammers: • Delivery Reports can be used to verify whether an address exists and so is available to be spammed • If the spammer uses a forged sender email address (E-mail spoofing), then the innocent email address that was used can be flooded with NDRs from the many invalid email addresses the spammer may have attempted to mail.

14

Email

15 These NDRs then constitute spam from the ISP to the innocent user

There are a number of systems that allow the sender to see if messages have been opened.[62] [63] [64] The receiver could also let the sender know that the emails have been opened through an "Okay" button. A check sign can appear in the sender's screen when the receiver's "Okay" button is pressed.

US Government The US Government has been involved in email in several different ways.

Starting in 1977, the US Postal Service (USPS) recognized that electronic mail and electronic transactions posed a significant threat to First Class mail volumes and revenue. Therefore, the USPS initiated an experimental email service known as E-COM. Electronic messages were transmitted to a post office, printed out, and delivered as hard copy. To take advantage of the service, an individual had to transmit at least 200 messages. The delivery time of the messages was the same as First Class mail and cost 26 cents. Both the Postal Regulatory Commission and the Federal Communications Commission opposed E-COM. The FCC concluded that E-COM constituted common carriage under its jurisdiction and the USPS would have to file a tariff.[65] Three years after initiating the service, USPS canceled E-COM and attempted to sell it off.[66] [67] [68] [69] [70] [71] The early ARPANET dealt with multiple email clients that had various, and at times incompatible, formats. For example, in the system Multics, the "@" sign meant "kill line" and anything after the "@" sign was ignored.[69] The Department of Defense DARPA desired to have uniformity and interoperability for email and therefore funded efforts to drive towards unified inter-operable standards. This led to David Crocker, John Vittal, Kenneth Pogran, and Austin Henderson publishing RFC 733, "Standard for the Format of ARPA Network Text Message" (November 21, 1977), which was apparently not effective. In 1979, a meeting was held at BBN to resolve incompatibility issues.

Jon Postel recounted the meeting in RFC 808, "Summary of Computer Mail Services Meeting Held at BBN on 10 January 1979" (March 1, 1982), which includes an appendix listing the varying email systems at the time. This, in turn, lead to the release of David Crocker's RFC 822, "Standard for the Format of ARPA Internet Text Messages" (August 13, 1982).[72] The National Science Foundation took over operations of the ARPANET and Internet from the Department of Defense, and initiated NSFNet, a new backbone for the network. A part of the NSFNet AUP forbade commercial traffic.[73] In 1988, Vint Cerf arranged for an interconnection of MCI Mail with NSFNET on an experimental basis.

The following year Compuserve email interconnected with NSFNET. Within a few years the commercial traffic restriction was removed from NSFNETs AUP, and NSFNET was privatised.

In the late 1990s, the Federal Trade Commission grew concerned with fraud transpiring in email, and initiated a series of procedures on spam, fraud, and phishing.[74] In 2004, FTC jurisdiction over spam was codified into law in the form of the CAN SPAM Act.[75] Several other US Federal Agencies have also exercised jurisdiction including the Department of Justice and the Secret Service.

Email

References [1] Klensin, J (October 2008). "RFC 5321 — Simple Mail Transfer Protocol" (http:/ / tools. ietf. org/ html/ rfc5321#section-2. 3. 11). Network Working Group. . Retrieved 2010-02-27.

[2] Long, Tony (23 October 2000). A Matter of (Wired News) Style (http:/ / www. nettime. org/ Lists-Archives/ nettime-bold-0010/ msg00471. html). Wired magazine. .

[3] Readers on (Wired News) Style (http:/ / www. wired. com/ culture/ lifestyle/ news/ 2000/ 10/ 39651). Wired magazine. 24 October 2000. .

[4] "RFC Editor Terms List" (http:/ / www. rfc-editor. org/ rfc-style-guide/ terms-online-03. txt). IETF. .

[5] Yahoo style guide (http:/ / styleguide. yahoo. com/ word-list/ e) [6] AP Stylebook editors share big changes (http:/ / www. aces2011. org/ sessions/ 18/ the-ap-stylebook-editors-visit-aces-2011/ ) from the American Copy Editors Society [7] Gerri Berendzen; Daniel Hunt. "AP changes e-mail to email" (http:/ / www. aces2011. org/ sessions/ 18/ the-ap-stylebook-editors-visit-aces-2011/ ). 15th National Conference of the American Copy Editors Society (2011, Phoenix). ACES. .

Retrieved 23 March 2011.

[8] AskOxford Language Query team. "What is the correct way to spell 'e' words such as 'email', 'ecommerce', 'egovernment'?" (http:/ / www. askoxford. com/ asktheexperts/ faq/ aboutspelling/ email). FAQ. Oxford University Press. . Retrieved 4 September 2009. "We recommend email, as this is now by far the most common form" [9] Reference.com (http:/ / dictionary. reference. com/ browse/ email) [10] Random House Unabridged Dictionary, 2006 [11] The American Heritage Dictionary of the English Language, Fourth Edition [12] Princeton University WordNet 3.0 [13] The American Heritage Science Dictionary, 2002 [14] ""Email" or "e-mail"" (http:/ / english. stackexchange. com/ questions/ 1925/ email-or-e-mail). English Language & Usage — Stack Exchange. August 25, 2010. . Retrieved September 26, 2010.

[15] RFC 821 (rfc821) - Simple Mail Transfer Protocol (http:/ / www. faqs. org/ rfcs/ rfc821. html) [16] RFC 1939 (rfc1939) - Post Office Protocol - Version 3 (http:/ / www. faqs. org/ rfcs/ rfc1939. html) [17] RFC 3501 (rfc3501) - Internet Message Access Protocol - version 4rev1 (http:/ / www. faqs. org/ rfcs/ rfc3501. html) [18] "RFC Style Guide", Table of decisions on consistent usage in RFC (http:/ / www. rfc-editor. org/ rfc-style-guide/ terms-online-03. txt) [19] Excerpt from the FAQ list of the Usenet newsgroup alt.usage.english (http:/ / alt-usage-english. org/ excerpts/ fxhowdoy. html) [20] See (Partridge 2008) for early history of email, from origins through 1991.

[21] "CTSS, Compatible Time-Sharing System" (September 4, 2006), University of South Alabama, USA-CTSS (http:/ / www. cis. usouthal. edu/ faculty/ daigle/ project1/ ctss. htm).

[22] Tom Van Vleck, "The IBM 7094 and CTSS" (September 10, 2004), Multicians.org (Multics), web: Multicians-7094 (http:/ / www. multicians. org/ thvv/ 7094. html).

[23] Tom Van Vleck's memoir of The History of Electronic Mail (http:/ / www. multicians. org/ thvv/ mail-history. html) [24] APL Quotations and Anecdotes (http:/ / www. jsoftware. com/ papers/ APLQA. htm), including Leslie Goldsmith's story of the Mailbox [25] History of the Internet, including Carter/Mondale use of email (http:/ / www. actewagl. com. au/ Education/ communications/ Internet/ historyOfTheInternet/ InternetOnItsInfancy. aspx) [26] Version 3 Unix mail(1) manual page from 10/25/1972 (http:/ / minnie. tuhs. org/ cgi-bin/ utree. pl?file=V3/ man/ man1/ mail. 1) [27] Version 6 Unix mail(1) manual page from 2/21/1975 (http:/ / minnie. tuhs. org/ cgi-bin/ utree. pl?file=V6/ usr/ man/ man1/ mail. 1) [28] Gordon Bell's timeline of Digital Equipment Corporation (https:/ / research. microsoft. com/ en-us/ um/ people/ gbell/ Digital/ timeline/ 1982. htm) [29] Version 7 Unix manual: "UUCP Implementation Description" by D. A. Nowitz, and "A Dial-Up Network of UNIX Systems" by D. A. Nowitz and M. E. Lesk (http:/ / cm. bell-labs. com/ 7thEdMan/ vol2/ uucp. bun) [30] Email History (http:/ / www. livinginternet. com/ e/ ei. htm) [31] The First Email (http:/ / openmap. bbn. com/ ~tomlinso/ ray/ firstemailframe. html) [32] Wave New World,Time Magazine, October 19, 2009, p.48 [33] How E-mail Works (http:/ / www. webcastr. com/ videos/ informational/ how-email-works. html). [internet video]. howstuffworks.com.

2008. .

[34] Simpson, Ken (October 3, 2008). "An update to the email standards" (http:/ / blog. mailchannels. com/ 2008/ 10/ update-to-email-standards. html). Mail Channels Blog Entry. .

[35] RFC 5322, 3.6. Field Definitions (http:/ / tools. ietf. org/ html/ rfc5322#section-3. 6) [36] RFC 5322, 3.6.4. Identification Fields (http:/ / tools. ietf. org/ html/ rfc5322#section-3. 6. 4) [37] http:/ / www. iana. org/ assignments/ message-headers/ perm-headers. html [38] http:/ / www. iana. org/ assignments/ message-headers/ prov-headers. html [39] Microsoft, Auto Response Suppress, 2010, microsoft reference (http:/ / msdn. microsoft. com/ en-us/ library/ ee219609(v=EXCHG. 80). aspx), 2010 Sep 22 [40] Craig Hunt (2002). TCP/IP Network Administration. O'Reilly Media. pp. 70. ISBN 978-0596002978.

[41] "Email policies that prevent viruses" (http:/ / advosys. ca/ papers/ mail-policies. html). .

16

Email [42] "When posting to a RootsWeb mailing list..." (http:/ / helpdesk. rootsweb. com/ listadmins/ plaintext. html) [43] "...Plain text, 72 characters per line..." (http:/ / www. openbsd. org/ mail. html) [44] How to Prevent the Winmail.dat File from Being Sent to Internet Users (http:/ / support. microsoft. com/ kb/ 138053) [45] In practice, some accepted messages may nowadays not be delivered to the recipient's InBox, but instead to a Spam or Junk folder which, especially in a corporate environment, may be inaccessible to the recipient [46] "File Extension .EML Details" (http:/ / filext. com/ file-extension/ EML). FILExt - The File Extension Source. . Retrieved 2009-09-26.

[47] RFC 2368 section 3 : by Paul Hoffman in 1998 discusses operation of the "mailto" URL. [48] Barrett, Grant (December 23, 2007). "All We Are Saying." (http:/ / www. nytimes. com/ 2007/ 12/ 23/ weekinreview/ 23buzzwords. html?ref=weekinreview). New York Times. . Retrieved 2007-12-24.

[49] "Email Right to Privacy - Why Small Businesses Care" (http:/ / www. smallbiztrends. com/ 2007/ 06/ email-has-right-to-privacy-why-small-businesses-care. html). Anita Campbell. 2007-06-19. .

[50] C. J. Hughes (February 17, 2011). "E-Mail May Be Binding, State Court Rules" (http:/ / www. nytimes. com/ 2011/ 02/ 20/ realestate/ 20posting. html). New York Times. . Retrieved 2011-02-20.

[51] http:/ / www. plantronics. com/ north_america/ en_US/ howwework/ [52] By Om Malik, GigaOm. â&#x20AC;&#x153; Is Email a Curse or a Boon? (http:/ / gigaom. com/ collaboration/ is-email-a-curse-or-a-boon/ )â&#x20AC;? September 22, 2010. Retrieved October 11, 2010.

[53] "Exchange 2007: Attachment Size Increase,..." (http:/ / technet. microsoft. com/ en-us/ magazine/ 2009. 01. exchangeqa. aspx?pr=blog).

TechNet Magazine, Microsoft.com US. 2010-03-25. .

[54] Lohr, Steve (2007-12-20). "Is Information Overload a $650 Billion Drag on the Economy?" (http:/ / bits. blogs. nytimes. com/ 2007/ 12/ 20/ is-information-overload-a-650-billion-drag-on-the-economy). New York Times. . Retrieved May 1, 2010.

[55] Stross, Randall (2008-04-20). "Struggling to Evade the E-Mail Tsunami" (http:/ / www. nytimes. com/ 2008/ 04/ 20/ technology/ 20digi. html?_r=2& oref=slogin& oref=slogin). New York Times. . Retrieved May 1, 2010.

[56] http:/ / gigaom. com/ collaboration/ is-email-a-curse-or-a-boon/ [57] "Did Darwin Skip Over Email?" (http:/ / www. foundrygroup. com/ blog/ archives/ 2008/ 04/ did-darwin-skip-over-email. php). Foundry Group. 2008-04-28. .

[58] Rich Kawanagh. The top ten email spam list of 2005. ITVibe news, 2006, january 02, ITvibe.com (http:/ / itvibe. com/ news/ 3837/ ) [59] How Microsoft is losing the war on spam Salon.com (http:/ / dir. salon. com/ story/ tech/ feature/ 2005/ 01/ 19/ microsoft_spam/ index. html) [60] Spam Bill 2003 ( PDF (http:/ / www. aph. gov. au/ library/ pubs/ bd/ 2003-04/ 04bd045. pdf)) [61] M. Toorani, SMEmail - A New Protocol for the Secure E-mail in Mobile Environments (http:/ / ieeexplore. ieee. org/ xpl/ freeabs_all. jsp?arnumber=4783292), Proceedings of the Australian Telecommunications Networks and Applications Conference (ATNAC'08), pp.39-44, Adelaide, Australia, December 2008. (arXiv:1002.3176) [62] About.com (http:/ / email. about. com/ od/ emailbehindthescenes/ a/ html_return_rcp. htm) [63] Webdevelopersnotes.com (http:/ / www. webdevelopersnotes. com/ tips/ yahoo/ notification-when-yahoo-email-is-opened. php) [64] Microsoft.com (http:/ / support. microsoft. com/ kb/ 222163) [65] In re Request for declaratory ruling and investigation by Graphnet Systems, Inc., concerning the proposed E-COM service, FCC Docket No. 79-6 (September 4, 1979) [66] History of the United States Postal Service, USPS (http:/ / www. usps. com/ history/ history/ his1. htm) [67] Hardy, Ian R; The Evolution of ARPANET Email (http:/ / www. archive. org/ web/ */ http:/ www. ifla. org/ documents/ internet/ hari1. txt); 1996-05-13; History Thesis Paper; University of California at Berkeley [68] James Bovard, The Law Dinosaur: The US Postal Service, CATO Policy Analysis (February 1985) [69] Jay Akkad, The History of Email (http:/ / www. cs. ucsb. edu/ ~almeroth/ classes/ F04. 176A/ homework1_good_papers/ jay-akkad. html) [70] US Postal Service: Postal Activities and Laws Related to Electronic Commerce, GAO-00-188 (http:/ / www. gao. gov/ archive/ 2000/ gg00188. pdf) [71] Implications of Electronic Mail and Message Systems for the U.S. Postal Service , Office of Technology Assessment, Congress of the United States, August 1982 (http:/ / govinfo. library. unt. edu/ ota/ Ota_4/ DATA/ 1982/ 8214. PDF) [72] Email History, How Email was Invented, Living Internet (http:/ / www. livinginternet. com/ e/ ei. htm) [73] Cybertelecom : Internet History (http:/ / www. cybertelecom. org/ notes/ internet_history80s. htm) [74] Cybertelecom : SPAM Reference (http:/ / www. cybertelecom. org/ spam/ Spamref. htm) [75] Cybertelecom : Can Spam Act (http:/ / www. cybertelecom. org/ spam/ canspam. htm)

17

Email

Further reading • Cemil Betanov, Introduction to X.400, Artech House, ISBN 0-89006-597-7.

• Lawrence Hughes, Internet e-mail Protocols, Standards and Implementation, Artech House Publishers, ISBN 0-89006-939-5.

• Kevin Johnson, Internet Email Protocols: A Developer's Guide, Addison-Wesley Professional, ISBN 0-201-43288-9.

• Pete Loshin, Essential Email Standards: RFCs and Protocols Made Practical, John Wiley & Sons, ISBN 0-471-34597-0.

• Partridge, Craig (April–June 2008). "The Technical Development of Internet Email" (http://www.ir.bbn.com/ ~craig/email.pdf) (PDF). IEEE Annals of the History of Computing (Berlin: IEEE Computer Society) 30 (2).

ISSN 1934-1547 • Sara Radicati, Electronic Mail: An Introduction to the X.400 Message Handling Standards, Mcgraw-Hill, ISBN 0-07-051104-7.

• John Rhoton, Programmer's Guide to Internet Mail: SMTP, POP, IMAP, and LDAP, Elsevier, ISBN 1-55558-212-5.

• John Rhoton, X.400 and SMTP: Battle of the E-mail Protocols, Elsevier, ISBN 1-55558-165-X. • David Wood, Programming Internet Mail, O'Reilly, ISBN 1-56592-479-7.

External links • E-mail (http://www.dmoz.org/Computers/Internet/E-mail//) at the Open Directory Project • IANA's list of standard header fields (http://www.iana.org/assignments/message-headers/perm-headers.html) • The History of Electronic Mail (http://www.multicians.org/thvv/mail-history.html) is a personal memoir by the implementer of an early email system

18

Instant messaging

Instant messaging Instant messaging (IM) is a form of real-time direct text-based communication between two or more people using personal computers or other devices, along with shared clients. The user's text is conveyed over a network, such as the Internet. More advanced instant messaging software clients also allow enhanced modes of communication, such as live voice or video calling.

Definition IM falls under the umbrella term online chat, as it is a real-time text-based networked communication system, but is distinct in that it is based on clients that facilitate connections between specified known users (often using "Buddy List", "Friend List" or "Contact List"), whereas online 'chat' also includes web-based applications that allow communication between (often anonymous) users in a multi-user environment.

Overview Instant messaging (IM) is a collection of technologies used for real-time text-based communication between two or more participants over the Internet, or other types of networks. Of importance is that online chat and instant messaging differs from other technologies such as e-mail due to Pidgin 2.0 running under GNOME the perceived synchronicity of the communications by the users 窶田hat happens in real-time. Some systems permit messages to be sent to people not currently 'logged on' (offline messages), thus removing some of the differences between IM and e-mail (often done by sending the message to the associated e-mail account).

IM allows effective and efficient communication, allowing immediate receipt of acknowledgment or reply. In many cases instant messaging includes additional features which can make it even more popular. For example, users can see each other by using webcams, or talk directly for free over the Internet using a microphone and headphones or loudspeakers. Many client programs allow file transfers as well, although they are typically limited in the permissible file-size.

It is typically possible to save a text conversation for later reference. Instant messages are often logged in a local message history, making it similar to the persistent nature of e-mails.

19

Instant messaging

History Instant messaging predates the Internet, first appearing on multi-user operating systems like CTSS and Multics[1] in the mid-1960s. Initially, some of these systems were used as notification systems for services like printing, but quickly were used to facilitate communication with other users logged in to the same machine. As networks developed, the protocols spread with the networks. Some of these used a peer-to-peer protocol (e.g. talk, ntalk and ytalk), while others required peers to connect to a server (see talker and IRC). During the Bulletin board system (BBS) phenomenon that In early instant messaging programs each character appeared when it was typed. peaked during the 1980s, some systems The UNIX "talk" command shown in this screenshot was popular in the 1980s and early 1990s. incorporated chat features which were similar to instant messaging; Freelancin' Roundtable was one prime example. The first[2] dedicated online chat service was the CompuServe CB Simulator in 1980,[3] created by CompuServe executive Alexander "Sandy" Trevor in Columbus, Ohio.

In the latter half of the 1980s and into the early 1990s, the Quantum Link online service for Commodore 64 computers offered user-to-user messages between currently connected customers, which they called "On-Line Messages" (or OLM for short), and later "FlashMail." (Quantum Link later became America Online and made AOL Instant Messenger (AIM), discussed later). While the Quantum Link service ran on a Commodore 64, using only the Commodore's PETSCII text-graphics, the screen was visually divided up into sections and OLMs would appear as a yellow bar saying "Message From:" and the name of the sender along with the message across the top of whatever the user was already doing, and presented a list of options for responding.[4] As such, it could be considered a sort of GUI (Graphical User Interface), albeit much more primitive than the later Unix, Windows and Macintosh based GUI IM software. OLMs were what Q-Link called "Plus Services" meaning they charged an extra per-minute fee on top of the monthly Q-Link access costs.

Modern, Internet-wide, GUI-based messaging clients as they are known today, began to take off in the mid 1990s with PowWow, ICQ, and AOL Instant Messenger. Similar functionality was offered by CU-SeeMe in 1992; though primarily an audio/video chat link, users could also send textual messages to each other. AOL later acquired Mirabilis, the authors of ICQ; a few years later ICQ (now owned by AOL) was awarded two patents for instant messaging by the U.S. patent office. Meanwhile, other companies developed their own software; (Excite, MSN, Ubique, and Yahoo), each with its own proprietary protocol and client; users therefore had to run multiple client applications if they wished to use more than one of these networks. In 1998, IBM released IBM Lotus Sametime, a product based on technology acquired when IBM bought Haifa-based Ubique and Lexington-based Databeam.

In 2000, an open source application and open standards-based protocol called Jabber was launched. The protocol was standardized under the name Extensible Messaging and Presence Protocol (XMPP). XMPP servers could act as gateways to other IM protocols, reducing the need to run multiple clients. Multi-protocol clients can use any of the popular IM protocols by using additional local libraries for each protocol. IBM Lotus Sametime's November 2007 release added IBM Lotus Sametime Gateway support for XMPP. In the current era, social networking providers often offer IM capabilities.

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Instant messaging

21

Many instant messaging services offer video calling features, Voice Over IP (VoIP) and web conferencing services.

Web conferencing services can integrate both video calling and instant messaging capabilities. Some instant messaging companies are also offering desktop sharing, IP radio, and IPTV to the voice and video features.

The term "Instant Messenger" is a service mark of Time Warner[5] and may not be used in software not affiliated with AOL in the United States. For this reason, the instant messaging client formerly known as Gaim (or gaim) announced, in April 2007, that they would be renamed "Pidgin".[6]

Clients Each modern IM service generally provides its own client, either a separately installed piece of software, or a browser-based client. These typically only work with that particular company's service, although some allow limited function with other services. There are also third party client software applications that will connect with most of the major IM services. Adium, Digsby, Jappix, Meebo, Miranda IM, Pidgin, Qnext and Trillian are a few of the common ones.

Interoperability Standard, complimentary instant messaging applications offer functions like file transfer, contact list(s), the ability to hold several simultaneous conversations, etc. These may be all the functions that a small business needs, but larger organizations will require more sophisticated applications that can work together.

The solution to finding applications capable of this is to use enterprise versions of instant messaging applications. These include titles like XMPP, Lotus Sametime, Microsoft Office Communicator, etc., which are often integrated with other enterprise applications such as workflow systems. These enterprise applications, or Enterprise Application Integration (EAI), are built to certain constraints, namely storing data in a common format.

There have been several attempts to create a unified standard for instant messaging: IETF's SIP (Session Initiation Protocol) and SIMPLE (SIP for Instant Messaging and Presence Leveraging Extensions), APEX (Application Exchange), Prim (Presence and Instant Messaging Protocol), the open XML-based XMPP (Extensible Messaging and Presence Protocol), and Open Mobile Alliance's Instant Messaging and Presence Service developed specifically for mobile devices.

Pidgin's tabbed chat window in Linux

Most attempts at producing a unified standard for the major IM providers (AOL, Yahoo! and Microsoft) have failed, and each continues to use its own proprietary protocol.

However, while discussions at IETF were stalled, Reuters signed the first inter-service provider connectivity agreement on September 2003. This agreement enabled AIM, ICQ and MSN Messenger users to talk with Reuters Messaging counterparts and vice-versa. Following this, Microsoft, Yahoo! and AOL agreed a deal in which Microsoft's Live Communications Server 2005 users would also have the possibility to talk to public instant messaging users. This deal established SIP/SIMPLE as a standard for protocol interoperability and established a connectivity fee for accessing public instant messaging groups or services. Separately, on 13 October 2005, Microsoft and Yahoo! announced that by the 3rd quarter of 2006 they would interoperate using SIP/SIMPLE, which was followed, in December 2005, by the AOL and Google strategic partnership deal in which Google Talk users would be able to communicate with AIM and ICQ users provided they have an AIM account.

There are two ways to combine the many disparate protocols:

Instant messaging • Combine the many disparate protocols inside the IM client application.

• Combine the many disparate protocols inside the IM server application. This approach moves the task of communicating with the other services to the server. Clients need not know or care about other IM protocols. For example, LCS 2005 Public IM Connectivity. This approach is popular in XMPP servers; however, the so-called transport projects suffer the same reverse engineering difficulties as any other project involved with closed protocols or formats.

Some approaches allow organizations to deploy their own, private instant messaging network by enabling them to restrict access to the server (often with the IM network entirely behind their firewall) and administer user permissions. Other corporate messaging systems allow registered users to also connect from outside the corporation LAN, by using an encrypted, firewall-friendly, HTTPS-based protocol. Typically, a dedicated corporate IM server has several advantages, such as pre-populated contact lists, integrated authentication, and better security and privacy.

Certain networks have made changes to prevent them from being utilized by such multi-network IM clients. For example, Trillian had to release several revisions and patches to allow its users to access the MSN, AOL, and Yahoo! networks, after changes were made to these networks. The major IM providers typically cite the need for formal agreements as well as security concerns as reasons for making these changes.

The use of proprietary protocols has meant that many instant messaging networks have been incompatible and people have been unable to reach friends on other networks. This has cost the instant messaging format dearly.[7]

Mobile instant messaging Mobile Instant Messaging (MIM) is the technology that allows Instant Messaging services to be accessed from a portable device, ranging from standard mobile phones, to smartphones (e.g. devices using operating systems such as iOS, Blackberry OS, Symbian OS, Android OS, Windows Mobile, et al.). It is done two ways: • Embedded Clients - tailored IM client for every specific device.

• Clientless Platform – a browser-based application that does not require downloading any software to the handset, and which enables all users and all devices from any network to connect to their Internet IM service– ideally. In practice, browser capabilities can pose problems.

In web browser Gmail has instant messaging capacity in webpage itself, which can be used in a web browser without the need to download and install the IM client. Later Yahoo and Hotmail also implemented it. eBuddy and Meebo websites offers instant messaging of different IM services. Generally such services are limited to text chat, although Gmail has voice and video capabilities. As of August 2010, Gmail allows the calling of regular phones from their web-based IM client.

Jappix is a XMPP web-client, offering the user a complete XMPP protocol features access, through his web browser.

It is declined in three versions: a desktop one, a mobile one and a mini one. The last one, Jappix Mini, is a mini chat for websites.

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Friend-to-friend networks Instant Messaging may be done in a Friend-to-friend network, in which each node connects to the friends on the friends list. This allows for communication with friends of friends and for the building of chatrooms for instant messages with all friends on that network.

IM language Users sometimes make use of internet slang or text speak to abbreviate common words or expressions in order to quicken conversations or to reduce keystrokes. The language has become universal, with well-known expressions such as 'lol' translated over to face to face language.

Emotions are often expressed in shorthand, such as the abbreviation LOL, BRB and TTYL (respectively Laugh(ing) Out Loud, Be Right Back and Talk To You Later).

Some, however, attempt to be more accurate with emotional expression over IM. Real time reactions such as (chortle) (snort) (guffaw) or (eye-roll) are becoming more popular. Also there are certain standards that are being introduced into mainstream conversations including, '#' indicates the use of sarcasm in a statement and '*' which indicates a spelling mistake and/or grammatical error in the previous message, followed by a correction.[8]

Business application Instant messaging has proven to be similar to personal computers, e-mail, and the World Wide Web, in that its adoption for use as a business communications medium was driven primarily by individual employees using consumer software at work, rather than by formal mandate or provisioning by corporate information technology departments. Tens of millions of the consumer IM accounts in use are being used for business purposes by employees of companies and other organizations.

In response to the demand for business-grade IM and the need to ensure security and legal compliance, a new type of instant messaging, called "Enterprise Instant Messaging" ("EIM") was created when Lotus Software launched IBM Lotus Sametime in 1998. Microsoft followed suit shortly thereafter with Microsoft Exchange Instant Messaging, later created a new platform called Microsoft Office Live Communications Server, and released Office Communications Server 2007 in October 2007. Oracle Corporation has also jumped into the market recently with its Oracle Beehive unified collaboration software.[9] Both IBM Lotus and Microsoft have introduced federation between their EIM systems and some of the public IM networks so that employees may use a single interface to both their internal EIM system and their contacts on AOL, MSN, and Yahoo!. Current leading EIM platforms include IBM Lotus Sametime, Microsoft Office Communications Server, Jabber XCP and Cisco Unified Presence. In addition, industry-focused EIM platforms as Reuters Messaging and Bloomberg Messaging provide enhanced IM capabilities to financial services companies.

The adoption of IM across corporate networks outside of the control of IT organizations creates risks and liabilities for companies who do not effectively manage and support IM use. Companies implement specialized IM archiving and security products and services to mitigate these risks and provide safe, secure, productive instant messaging capabilities to their employees.

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Review of products IM products can typically be categorised into two types: Enterprise Instant Messaging (EIM)[10] and Consumer Instant Messaging (CIM).[11] Enterprise solutions use an internal IM server, however this isn't always feasible, particularly for smaller businesses with limited budgets. The second option, using a CIM provides the advantage of being inexpensive to implement and has little need for investing in new hardware or server software.

For corporate use encryption and conversation archiving are usually regarded as important features due to security concerns. Sometimes the use of different operating systems in organizations calls for the use of software that supports more than one platform. For example many software companies use Windows XP in administration departments but have software developers who use Linux.

Risks and liabilities Although instant messaging delivers many benefits, it also carries with it certain risks and liabilities, particularly when used in workplaces. Among these risks and liabilities are: • Security risks (e.g. IM used to infect computers with spyware, viruses, trojans, worms) • Compliance risks • Inappropriate use • Trade secret leakage

Security risks Crackers (malicious "hacker" or [black hat] hacker) have consistently used IM networks as vectors for delivering phishing attempts, "poison URLs", and virus-laden file attachments from 2004 to the present, with over 1100 discrete attacks listed by the IM Security Center[12] in 2004-2007. Hackers use two methods of delivering malicious code through IM: delivery of viruses, trojan horses, or spyware within an infected file, and the use of "socially engineered" text with a web address that entices the recipient to click on a URL connecting him or her to a website that then downloads malicious code. Viruses, computer worms, and trojans typically propagate by sending themselves rapidly through the infected user's buddy list. An effective attack using a poisoned URL may reach tens of thousands of people in a short period when each person's buddy list receives messages appearing to be from a trusted friend. The recipients click on the web address, and the entire cycle starts again. Infections may range from nuisance to criminal, and are becoming more sophisticated each year.

IM connections usually take place in plain text, making them susceptible to eavesdropping. In addition, IM client software often requires the user to expose open UDP ports to the world, increasing the threat posed by potential security vulnerabilities.[13]

Compliance risks In addition to the malicious code threat, the use of instant messaging at work also creates a risk of non-compliance to laws and regulations governing the use of electronic communications in businesses. In the United States alone there are over 10,000 laws and regulations related to electronic messaging and records retention.[14] The better-known of these include the Sarbanes-Oxley Act, HIPAA, and SEC 17a-3. Clarification from the Financial Industry Regulatory Authority ("FINRA") was issued to member firms in the financial services industry in December, 2007, noting that "electronic communications", "email", and "electronic correspondence" may be used interchangeably and can include such forms of electronic messaging as instant messaging and text messaging.[15] Changes to Federal Rules of Civil Procedure, effective December 1, 2006, created a new category for electronic records which may be requested during discovery in legal proceedings. Most countries around the world also regulate the use of electronic messaging and electronic records retention in similar fashion to the United States. The most common regulations related to IM at work involve the need to produce archived business communications to satisfy government or judicial requests

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25

under law. Many instant messaging communications fall into the category of business communications that must be archived and retrievable.

Inappropriate use Organizations of all types must protect themselves from the liability of their employees' inappropriate use of IM. The informal, immediate, and ostensibly anonymous nature of instant messaging makes it a candidate for abuse in the workplace. The topic of inappropriate IM use became front page news in October 2006 when U.S. Congressman Mark Foley resigned his seat after admitting sending offensive instant messages of a sexual nature to underage former House pages from his Congressional office PC. The Mark Foley Scandal led to media coverage and mainstream newspaper articles warning of the risks of inappropriate IM use in workplaces. In most countries, corporations have a legal responsibility to ensure harassment-free work environment for employees. The use of corporate-owned computers, networks, and software to harass an individual or spread inappropriate jokes or language creates a liability for not only the offender but also the employer. A survey by IM archiving and security provider Akonix Systems, Inc. in March 2007 showed that 31% of respondents had been harassed over IM at work.[16] Companies now include instant messaging as an integral component of their policies on appropriate use of the World Wide Web, e-mail, and other corporate assets.

Security and archiving In the early 2000s, a new class of IT security provider emerged to provide remedies for the risks and liabilities faced by corporations who chose to use IM for business communications. The IM security providers created new products to be installed in corporate networks for the purpose of archiving, content-scanning, and security-scanning IM traffic moving in and out of the corporation. Similar to the e-mail filtering vendors, the IM security providers focus on the risks and liabilities described above.

With rapid adoption of IM in the workplace, demand for IM security products began to grow in the mid-2000s. By 2007, the preferred platform for the purchase of security software had become the "computer appliance", according to IDC, who estimate that by 2008, 80% of network security products will be delivered via an appliance.[17]

User base Note that many of the numbers listed in this section are not directly comparable, and some are speculative. While some numbers are given by the owners of a complete instant messaging system, others are provided by commercial vendors of a part of a distributed system. Some companies may be motivated to inflate their numbers in order to increase advertisement earnings or to attract partners, clients, or customers. Importantly, some numbers are reported as the number of "active" users (without a shared standard of that activity), others indicate total user accounts, while others indicate only the users logged in during an instance of peak usage.

Service AIM

User count

Date/source [18]

53 million active

September 2006

>100 million total

January 2006

eBuddy

35 million total

October 2006

Gadu-Gadu

Over 6 million active (majority in Poland)

May 2009

IBM Lotus Sametime

40 million total (licensed, entitled users in enterprises)

December 2009

ICQ

50 million active

CNET February 8, 2010

[19] [20]

, including 4 million mobile users

[21]

[22]

Instant messaging

26 [23]

IMVU

1 million total

June 2007

Mail.ru Agent

1 million active (daily)

September 2006

Meebo

1 million total

October 2006

MXit

11 million total (9 million in South Africa)

29 January 2009

Paltalk

3.3 million unique visitors per month

August 2006

PSYC

1 million active (daily) (majority in Brazil)

[28] February 2007 . Note that these users are part of the IRC user base, messaging user base consists of a few hundred users

Skype

27 million peak online

January 2011 [29]

763 million total

as of January, 13th, 2011 (can be checked when searching users in Skype 5.x)

Claimed 100 million peak online (majority in China)

QQ's official website

Tencent QQ

[24]

[25] [26]

.

[27]

[30]

Claimed 440 million active accounts (includes users Q's official website[30] with multiple accounts). (majority in China) [30]

Claimed 990 million total registered accounts. (majority in China)

Q's official website

VZOchat

>550,000

December 2008

Windows Live Messenger (previously MSN Messenger)

330 million active

June 2009

Xfire

16 million total

May 2010

Yahoo! Messenger

248 million active registered Yahoo global users (refers to ALL Yahoo users not Instant Messaging users)

17 Jan 2008

Facebook

Claimed 500 million active users

Facebook statistics

Blauk

700, 000 users each day

[36]

[31]

[32]

[33] [34]

[35]

References [1] [2] [3] [4] [5]

Instant Messaging on CTSS and Multics (http:/ / www. multicians. org/ thvv/ mail-history. html) CompuServe Innovator Resigns After 25 Years, The Columbus Dispatch, 11 May 1996, p. 2F Wired and Inspired, The Columbus Dispatch (Business page), by Mike Pramik, 12 November 2000 Screenshot of a Quantum Link OLM (http:/ / www. qlinklives. org/ qlink-old/ liz1. jpg) Summary of final decisions issued by the trademark trial and appeal board, January 16-20, 2006 (http:/ / www. uspto. gov/ web/ offices/ com/ sol/ foia/ ttab/ decsum/ 2006/ 16jan06. pdf) [6] "Important and Long Delayed News" (http:/ / www. pidgin. im/ index. php?id=177), Announcement of Gaim renaming (to Pidgin), April 6, 2007 [7] "The decline of instant messaging" (http:/ / news. bbc. co. uk/ 2/ hi/ uk_news/ magazine/ 8698174. stm). BBC News. 2010-05-24. .

[8] Instant Messaging (http:/ / wiki. networkdictionary. com/ index. php/ Instant_Messenging), NetworkDictionary.com.

[9] "Oracle Buzzes with Updates for its Beehive Collaboration Platform" (http:/ / www. cmswire. com/ cms/ enterprise-20/ oracle-buzzes-with-updates-for-its-beehive-collaboration-platform-004538. php). CMSWire. 2009-05-06. . Retrieved 2009-07-16.

[10] http:/ / im. about. com/ od/ imforbusiness/ a/ topbizims. htm [11] http:/ / im. about. com/ b/ 2008/ 03/ 15/ reader-questions-im-privacy-at-work. htm [12] "IM Security Center" (http:/ / www. imsecuritycenter. com). . Retrieved 2007-05-13.

[13] "Why just say no to IM at work" (http:/ / blog. anta. net/ 2009/ 10/ 28/ why-just-say-no-to-im-at-work/ ). blog.anta.net. 2009-10-29.

ISSNÂ 1797-1993. . Retrieved 2009-10-29.

Instant messaging [14] "ESG compliance report excerpt, Part 1: Introduction" (http:/ / searchstorage. techtarget. com/ tip/ 0,289483,sid5_gci906152,00. html). .

Retrieved 2007-05-13.

[15] FINRA, Regulatory Notice 07-59, Supervision of Electronic Communications, December 2007 [16] "Akonix Warns Corporations of Risqué Employee IM Behavior" (http:/ / www. akonix. com/ press/ releases-details. asp?id=130). .

Retrieved 2007-05-13.

[17] Chris Christiansen and Rose Ryan, International Data Corp., "IDC Telebriefing: Threat Management Security Appliance Review and Forecast" [18] http:/ / arstechnica. com/ news. ars/ post/ 20060927-7846. html [19] http:/ / www. aol. co. uk [20] http:/ / www. ebuddy. com/ press. php [21] http:/ / www. audyt. gemius. pl/ pages/ display/ komuniatory-uzytkownicy [22] http:/ / news. cnet. com/ 8301-1023_3-10449039-93. html [23] http:/ / www. imvu. com/ catalog/ web_info. php?section=Info& topic=aboutus [24] http:/ / www. cnews. ru/ news/ line/ index. shtml?2006/ 09/ 14/ 211037 [25] http:/ / blog. meebo. com/ ?p=258 [26] http:/ / www. itweb. co. za/ sections/ business/ 2009/ 0901291031. asp?S=Cellular& A=CEL& O=FRGN [27] http:/ / www. comscore. com/ metrix/ [28] http:/ / about. psyc. eu/ Index#How_many_people_use_this_stuff. 3F [29] http:/ / news. softpedia. com/ news/ Skype-Usage-Surges-as-27-Million-People-Chat-Simultaneously-177523. shtml [30] QQ website - History (http:/ / im. qq. com/ culture) [31] http:/ / vzochat. com [32] http:/ / messengersays. spaces. live. com/ Blog/ cns!5B410F7FD930829E!73591. entry [33] [34] [35] [36]

http:/ / www. xfire. com/ http:/ / www. searchenginejournal. com/ yahoo-to-support-openid-for-its-248-million-users-openid-to-support-yahoo-ids/ 6258/ http:/ / www. facebook. com/ press/ info. php?statistics http:/ / www. sharenator. com/ w/ blauk. com

External links • Instant messaging (http://www.dmoz.org/Computers/Internet/Chat/Instant_Messaging//) at the Open Directory Project • "Global Instant Messaging Market Share" (http://billionsconnected.com/blog/2008/08/ global-im-market-share-im-usage/) - CC-Licensed market share data.

• IM and LAN messengers (http://www.filesland.com/software/lan-messenger.html) List of IM and LAN messaging software

27

Social networking service

Social networking service A social networking service is an online service, platform, or site that focuses on building and reflecting of social networks or social relations among people, e.g., who share interests and/or activities. A social network service essentially consists of a representation of each user (often a profile), his/her social links, and a variety of additional services. Most social network services are web based and provide means for users to interact over the internet, such as e-mail and instant messaging. Online community services are sometimes considered as a social network service, though in a broader sense, social network service usually means an individual-centered service whereas online community services are group-centered. Social networking sites allow users to share ideas, activities, events, and interests within their individual networks.

The main types of social networking services are those which contain category places (such as former school year or classmates), means to connect with friends (usually with self-description pages) and a recommendation system linked to trust. Popular methods now combine many of these, with Facebook and Twitter widely used worldwide, Nexopia (mostly in Canada);[1] Bebo,[2] VKontakte, Hi5, Hyves (mostly in The Netherlands), Draugiem.lv (mostly in Latvia), StudiVZ (mostly in Germany), iWiW (mostly in Hungary), Tuenti (mostly in Spain), Nasza-Klasa (mostly in Poland), Decayenne, Tagged, XING,[3] Badoo[4] and Skyrock in parts of Europe;[5] Orkut and Hi5 in South America and Central America;[6] and Friendster, Mixi, Multiply, Orkut, Wretch, renren and Cyworld in Asia and the Pacific Islands and Twitter, Facebook, LinkedIn and Orkut are very popular in India.

There have been attempts to standardize these services to avoid the need to duplicate entries of friends and interests (see the FOAF standard and the Open Source Initiative).

History The potential for computer networking to facilitate new forms of computer-mediated social interaction was suggested early on.[7] Efforts to support social networks via computer-mediated communication were made in many early online services, including Usenet, ARPANET, LISTSERV, and bulletin board services (BBS). Many prototypical features of social networking sites were also present in online services such as America Online, Prodigy, and CompuServe.

Early social networking on the World Wide Web began in the form of generalized online communities such as Theglobe.com (1995),[8] Geocities (1994) and Tripod.com (1995). Many of these early communities focused on bringing people together to interact with each other through chat rooms, and encouraged users to share personal information and ideas via personal webpages by providing easy-to-use publishing tools and free or inexpensive webspace. Some communities - such as Classmates.com - took a different approach by simply having people link to each other via email addresses. In the late 1990s, user profiles became a central feature of social networking sites, allowing users to compile lists of "friends" and search for other users with similar interests.

New social networking methods were developed by the end of the 1990s, and many sites began to develop more advanced features for users to find and manage friends.[9] This newer generation of social networking sites began to flourish with the emergence of SixDegrees.com in 1997,[10] followed by Makeoutclub in 2000,[11] [12] , Friendster in 2002,[13] and soon became part of the Internet mainstream. Friendster was followed by MySpace and LinkedIn a year later, and finally, Bebo. Attesting to the rapid increase in social networking sites' popularity, by 2005, MySpace was reportedly getting more page views than Google.

Facebook,[14] launched in 2004, has since become the largest social networking site in the world.[15] Today, it is estimated that there are now over 200 active sites using a wide variety of social networking models.

28

Social networking service

Social impacts Web based social networking services make it possible to connect people who share interests and activities across political, economic, and geographic borders.[16] Through e-mail and instant messaging, online communities are created where a gift economy and reciprocal altruism are encouraged through cooperation. Information is particularly suited to gift economy, as information is a nonrival good and can be gifted at practically no cost.[17] [18] Facebook and other social networking tools are increasingly the object of scholarly research. Scholars in many fields have begun to investigate the impact of social networking sites, investigating how such sites may play into issues of identity, privacy,[19] social capital, youth culture, and education danah boyd, (2007), Why Youth (Heart) Social Network Sites [20], MacArthur Foundation Series on Digital Learning - Youth, Identity, and Digital Media Volume (ed. David Buckingham). MIT Press</ref> Several websites are beginning to tap into the power of the social networking model for philanthropy. Such models provide a means for connecting otherwise fragmented industries and small organizations without the resources to reach a broader audience with interested users.[21] Social networks are providing a different way for individuals to communicate digitally. These communities of hypertexts allow for the sharing of information and ideas, an old concept placed in a digital environment.

In 2011, HCL Technologies conducted research which showed that 50% of British employers had banned the use of social networking sites/ services during office hours. [22] [23]

Typical structure Basics Social networking sites to share some conventional features. Most often, individual users are encouraged to create profiles containing various information about themselves. Users can often upload pictures of themselves to their profiles, post blog entries for others to read, search for other users with similar interests, and compile and share lists of contacts. In addition, user profiles often have a section dedicated to comments from friends and other users. To protect user privacy, social networks usually have controls that allow users to choose who can view their profile, contact them, add them to their list of contacts, and so on.

In recent years, it has also become common for a wide variety of organizations to create profiles to advertise products and services.

Additional features Some social networks have additional features, such as the ability to create groups that share common interests or affiliations, upload or stream live videos, and hold discussions in forums. Geosocial networking co-opts internet mapping services to organize user participation around geographic features and their attributes.

There is also a trend for more interoperability between social networks led by technologies such as OpenID and OpenSocial.

Lately, mobile social networking has become popular. In most mobile communities, mobile phone users can now create their own profiles, make friends, participate in chat rooms, create chat rooms, hold private conversations, share photos and videos, and share blogs by using their mobile phone. Some companies provide wireless services which allow their customers to build their own mobile community and brand it, but one of the most popular wireless services for social networking in North America is Facebook Mobile.

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Social networking service

Emerging trends in social networking As the increase in popularity of social networking is on a constant rise,[24] new uses for the technology are constantly being observed.

At the forefront of emerging trends in social networking sites is the concept of "real-time web" and "location based."

Real time allows users to contribute content, which is then broadcasted as it is being uploaded - the concept is analogous to live radio and television broadcasts. Twitter set the trend for "real time" services, where users can broadcast to the world what they are doing, or what is on their minds within a 140 character limit. Facebook followed suit with their "Live Feed" where users' activities are streamed as soon as it happens.While Twitter focuses on words, Clixtr, another real time service, focuses on group photo sharing where users can update their photo streams with photos while at an event. Friends and nearby users can contribute their own photos and comments to that event stream, thus contributing to the "real time" aspect of broadcasting photos and comments as it is being uploaded. In the location based social networking space, Foursquare gained popularity as it allowed for users to "check-in" to places that they are frequenting at that moment. Gowalla is another such service which functions in much the same way that Foursquare does, leveraging the GPS in phones to create a location-based user experience.

Clixtr, though in the real time space, is also a location based social networking site since events created by users are automatically geotagged, and users can view events occurring nearby through the Clixtr iPhone app. Recently, Yelp announced its entrance into the location based social networking space through check-ins with their mobile app; whether or not this becomes detrimental to Foursquare or Gowalla is yet to be seen as it is still considered a new space in the internet technology industry.[25] One popular use for this new technology is social networking between businesses. Companies have found that social networking sites such as Facebook and Twitter are great ways to build their brand image. According to Jody Nimetz, author of Marketing Jive,[26] there are five major uses for businesses and social media: to create brand awareness, as an online reputation management tool, for recruiting, to learn about new technologies and competitors, and as a lead gen tool to intercept potential prospects.[26] These companies are able to drive traffic to their own online sites while encouraging their consumers and clients to have discussions on how to improve or change products or services.

One other use that is being discussed is the use of Social Networks in the Science communities. Julia Porter Liebeskind et al. have published a study on how New Biotechnology Firms are using social networking sites to share exchanges in scientific knowledge.[27] They state in their study that by sharing information and knowledge with one another, they are able to "increase both their learning and their flexibility in ways that would not be possible within a self-contained hierarchical organization." Social networking is allowing scientific groups to expand their knowledge base and share ideas, and without these new means of communicating their theories might become "isolated and irrelevant".

Social networks are also being used by teachers and students as a communication tool. Because many students are already using a wide-range of social networking sites, teachers have begun to familiarize themselves with this trend and are now using it to their advantage. Teachers and professors are doing everything from creating chat-room forums and groups to extend classroom discussion to posting assignments, tests and quizzes, to assisting with homework outside of the classroom setting. Social networks are also being used to foster teacher-parent communication. These sites make it possible and more convenient for parents to ask questions and voice concerns without having to meet face-to-face.

Social networks are being used by activists as a means of low-cost grassroots organizing. Extensive use of an array of social networking sites enabled organizers of the 2009 National Equality March to mobilize an estimated 200,000 participants to march on Washington with a cost savings of up to 85% per participant over previous methods.[28] The use of online social networks by libraries is also an increasingly prevalent and growing tool that is being used to communicate with more potential library users, as well as extending the services provided by individual libraries.

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Social networking service A final rise in social network use is being driven by college students using the services to network with professionals for internship and job opportunities. Many studies have been done on the effectiveness of networking online in a college setting, and one notable one is by Phipps Arabie and Yoram Wind published in Advances in Social Network Analysis.[29]

Social network hosting service A social network hosting service is a web hosting service that specifically hosts the user creation of web-based social networking services, alongside related applications. Such services are also known as vertical social networks due to the creation of SNSes which cater to specific user interests and niches; like larger, interest-agnostic SNSes, such niche networking services may also possess the ability to create increasingly niche groups of users.

Business model Few social networks currently charge money for membership. In part, this may be because social networking is a relatively new service, and the value of using them has not been firmly established in customers' minds. Companies such as MySpace and Facebook sell online advertising on their site. Their business model is based upon large membership count, and charging for membership would be counterproductive.[30] Some believe that the deeper information that the sites have on each user will allow much better targeted advertising than any other site can currently provide.[31] Social networks operate under an autonomous business model, in which a social network's members serve dual roles as both the suppliers and the consumers of content. This is in contrast to a traditional business model, where the suppliers and consumers are distinct agents. Revenue is typically gained in the autonomous business model via advertisements, but subscription-based revenue is possible when membership and content levels are sufficiently high.[32]

Issues Privacy Privacy Concerns with social networking services have been raised growing concerns amongst users on the dangers of giving out too much personal information and the threat of sexual predators. Users of these services also need to be aware of data theft or viruses. However, large services, such as MySpace and Netlog, often work with law enforcement to try to prevent such incidents.

In addition, there is a perceived privacy threat in relation to placing too much personal information in the hands of large corporations or governmental bodies, allowing a profile to be produced on an individual's behavior on which decisions, detrimental to an individual, may be taken.

Furthermore, there is an issue over the control of dataâ&#x20AC;&#x201D;information that was altered or removed by the user may in fact be retained and/or passed to 3rd parties. This danger was highlighted when the controversial social networking site Quechup harvested e-mail addresses from users' e-mail accounts for use in a spamming operation.[33] In medical and scientific research, asking subjects for information about their behaviors is normally strictly scrutinized by institutional review boards, for example, to ensure that adolescents and their parents have informed consent. It is not clear whether the same rules apply to researchers who collect data from social networking sites.

These sites often contain a great deal of data that is hard to obtain via traditional means. Even though the data are public, republishing it in a research paper might be considered invasion of privacy.[34] Privacy on social networking sites can be undermined by many factors. For example, users may disclose personal information, sites may not take adequate steps to protect user privacy, and third parties frequently use information posted on social networks for a variety of purposes. "For the Net generation, social networking sites have become the

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Social networking service preferred forum for social interactions, from posturing and role playing to simply sounding off. However, because such forums are relatively easy to access, posted content can be reviewed by anyone with an interest in the users' personal information".[35] [36] [37] Following plans by the UK government to monitor traffic on social networks[38] schemes similar to E-mail jamming have been proposed for networks such as Twitter and Facebook. These would involve "friending" and "following" large numbers of random people to thwart attempts at network analysis.

Notifications on websites There has been a trend for social networking sites to send out only 'positive' notifications to users. For example sites such as Bebo, Facebook, and Myspace will not send notifications to users when they are removed from a person's friends list. Similarly Bebo will send out a notification if a user is moved to the top of another user's friends list but no notification is sent if they are moved down the list.

This allows users to purge undesirables from their list extremely easily and often without confrontation since a user will rarely notice if one person disappears from their friends list. It also enforces the general positive atmosphere of the website without drawing attention to unpleasant happenings such as friends falling out, rejection and failed relationships.

Access to information Many social networking services, such as Facebook, provide the user with a choice of who can view their profile.

This prevents unauthorized user(s) from accessing their information.[39] Parents who want to access their child's MySpace or Facebook account have become a big problem for teenagers who do not want their profile seen by their parents. By making their profile private, teens can select who may see their page, allowing only people added as "friends" to view their profile and preventing unwanted viewing of the profile by parents. Most teens are constantly trying to create a structural barrier between their private life and their parents.[40] To edit information on a certain social networking service account, the social networking sites require you to login or provide a password. This prevents unauthorized user(s) from adding, changing, or removing personal information, pictures, and/or other data.

Potential for misuse The relative freedom afforded by social networking services has caused concern regarding the potential of its misuse by individual patrons. In October 2006, a fake Myspace profile created in the name of Josh Evans by Lori Janine Drew led to the suicide of Megan Meier.[41] The event incited global concern regarding the use of social networking services for bullying purposes In July 2008, a Briton, Grant Raphael, was ordered to pay a total of GBP ÂŁ22,000 (about USD $44,000) for libel and breach of privacy. Raphael had posted a fake page on Facebook purporting to be that of a former schoolfriend Matthew Firsht, with whom Raphael had fallen out in 2000. The page falsely claimed that Firsht was homosexual and that he was dishonest.

At the same time, genuine use of social networking services has been treated with suspicion on the ground of the services' misuse. In September 2008, the profile of Australian Facebook user Elmo Keep was banned by the site's administrators on the grounds that it violated the site's terms of use. Keep is one of several users of Facebook who were banned from the site on the presumption that their names aren't real, as they bear resemblance the names of characters like Sesame Street's Elmo.[42]

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Risk for child safety Citizens and governments have been concerned by a misuse by child and teenagers of social networking services, particularly in relation to online sexual predators. A certain number of actions have been engaged by governments to better understand the problem and find some solutions. A 2008 panel concluded that technological fixes such as age verification and scans are relatively ineffective means of apprehending online predators.[43] In May 2010, a child pornography social networking site with hundreds of members was dismantled by law enforcement. It was deemed "the largest crimes against children case brought anywhere by anyone."[44]

Trolling A common misuse of social networking sites such as Facebook is that it is occasionally used to emotionally abuse individuals. Such actions are often referred to as trolling. It is not rare for confrontations in the real world to be translated online. Trolling can occur in many different forms, such as (but not limited to) defacement of deceased person(s) tribute pages, name calling, playing online pranks on volatile individuals and controversial comments with the intention to cause anger and cause arguments. Trolling is not to be confused with cyber-bullying.

Online bullying Online bullying (aka "Cyber-bullying") is a relatively common occurrence and it can often result in emotional trauma for the victim. Depending on the networking outlet, up to 39% of users admit to being â&#x20AC;&#x153;cyber-bulliedâ&#x20AC;?.[45] Danah Boyd, a researcher of social networks quotes a teenager in her article, Why Youth (Heart) Social Network Sites. The teenager expresses frustration towards networking sites like MySpace because it causes drama and too much emotional stress.[46] There are not many limitations as to what individuals can post when online. Inherently individuals are given the power to post offensive remarks or pictures that could potentially cause a great amount of emotional pain for another individual.

Interpersonal communication Interpersonal communication has been a growing issue as more and more people have turned to social networking as a means of communication."Benniger (1987) describes how mass media has gradually replaced interpersonal communication as a socializing force. Further, social networking sites have become popular sites for youth culture to explore themselves, relationships, and share cultural artifacts". A Privacy Paradox [47] Many teens and social networking users may be harming their interpersonal communication by using sites such as Facebook and MySpace.

Stated by Baroness Greenfield, an Oxford University Neuroscientist, "My fear is that these technologies are infantilizing the brain into the state of small children who are attracted by buzzing noises and bright lights, who have a small attention span and who live for the moment."[48]

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Patents There has been rapid growth in the number of US patent applications that cover new technologies related to social networking. The number of published applications has been growing rapidly since 2003. There are now over 3500 published applications. As many as 7000 applications may be currently on file including those that haven't been published yet.[49] Only about 400 [50] of these applications have issued as patents, however, largely due to the multi-year backlog in examination of business method patents and the difficulty in getting these patent applications allowed.[51] Number of US social network patent applications

It has been reported that social networking patents are important for the published per year and patents issued per year establishment of new start up companies.[52] It has also been reported, however, that social networking patents inhibit innovation.[53] On June 15, 2010, the United States Patent and Trademark Office awarded Amazon.com a patent for "Social Networking System" based on its ownership of PlanetAll.[54] The patent describes a Social Networking System as A networked computer system provides various services for assisting users in locating, and establishing contact relationships with, other users. For example, in one embodiment, users can identify other users based on their affiliations with particular schools or other organizations. The system also provides a mechanism for a user to selectively establish contact relationships or connections with other users, and to grant permissions for such other users to view personal information of the user. The system may also include features for enabling users to identify contacts of their respective contacts. In addition, the system may automatically notify users of personal information updates made by their respective contacts.[55] The patent has garnered attention due to its similarity to the popular social networking site Facebook.[56]

Investigations Social networking services are increasingly being used in legal and criminal investigations. Information posted on sites such as MySpace and Facebook has been used by police (forensic profiling), probation, and university officials to prosecute users of said sites. In some situations, content posted on MySpace has been used in court.[57] Facebook is increasingly being used by school administrations and law enforcement agencies as a source of evidence against student users. The site, the number one online destination for college students, allows users to create profile pages with personal details. These pages can be viewed by other registered users from the same school which often include resident assistants and campus police who have signed-up for the service.[58] One UK police force has sifted pictures from Facebook and arrested some people who had been photographed in a public place holding a weapon such as a knife (having a weapon in a public place is illegal).[59]

Application domains Government applications Social networking is more recently being used by various government agencies. Social networking tools serve as a quick and easy way for the government to get the opinion of the public and to keep the public updated on their activity. The Centers for Disease Control demonstrated the importance of vaccinations on the popular children's site Whyville and the National Oceanic and Atmospheric Administration has a virtual island on Second Life where people can explore underground caves or explore the effects of global warming.[60] Similarly, NASA has taken advantage of a few social networking tools, including Twitter and Flickr. They are using these tools to aid the

Social networking service Review of U.S. Human Space Flight Plans Committee, whose goal it is to ensure that the nation is on a vigorous and sustainable path to achieving its boldest aspirations in space.[61]

Business applications The use of social networking services in an enterprise context presents the potential of having a major impact on the world of business and work (Fraser & Dutta 2008).

Social networks connect people at low cost; this can be beneficial for entrepreneurs and small businesses looking to expand their contact bases. These networks often act as a customer relationship management tool for companies selling products and services. Companies can also use social networks for advertising in the form of banners and text ads. Since businesses operate globally, social networks can make it easier to keep in touch with contacts around the world.

One example of social networking being used for business purposes is LinkedIn.com, which aims to interconnect professionals. LinkedIn has over 100 million users in over 200 countries.[62] Another is the use of physical spaces available to members of a social network such as Hub Culture, an invitation only social network for entrepreneurs, and other business influentials, with Pavilions in major cities such as London, UK. Having a physical presence allows members to network in the real world, as well as the virtual, adding extra business value.

Applications for social networking sites have extended toward businesses and brands are creating their own, high functioning sites, a sector known as brand networking. It is the idea a brand can build its consumer relationship by connecting their consumers to the brand image on a platform that provides them relative content, elements of participation, and a ranking or score system. Brand networking is a new way to capitalize on social trends as a marketing tool.

Dating applications Many social networks provide an online environment for people to communicate and exchange personal information for dating purposes. Intentions can vary from looking for a one time date, short-term relationships, and long-term relationships.[63] Most of these social networks, just like online dating services, require users to give out certain pieces of information.

This usually includes a user's age, gender, location, interests, and perhaps a picture. Releasing very personal information is usually discouraged for safety reasons.[64] This allows other users to search or be searched by some sort of criteria, but at the same time people can maintain a degree of anonymity similar to most online dating services. Online dating sites are similar to social networks in the sense that users create profiles to meet and communicate with others, but their activities on such sites are for the sole purpose of finding a person of interest to date. Social networks do not necessarily have to be for dating; many users simply use it for keeping in touch with friends, and colleagues.[65] However, an important difference between social networks and online dating services is the fact that online dating sites usually require a fee, where social networks are free.[66] This difference is one of the reasons the online dating industry is seeing a massive decrease in revenue due to many users opting to use social networking services instead.

Many popular online dating services such as Match.com, Yahoo Personals, and eHarmony.com are seeing a decrease in users, where social networks like MySpace and Facebook are experiencing an increase in users.[67] The number of internet users in the U.S. that visit online dating sites has fallen from a peak of 21% in 2003 to 10% in 2006.[68] Whether its the cost of the services, the variety of users with different intentions, or any other reason, it is undeniable that social networking sites are quickly becoming the new way to find dates online.

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Educational applications The National School Boards Association reports that almost 60 percent of students who use social networking talk about education topics online and, surprisingly, more than 50 percent talk specifically about schoolwork. Yet the vast majority of school districts have stringent rules against nearly all forms of social networking during the school day â&#x20AC;&#x201D; even though students and parents report few problem behaviors online.

Social networks focused on supporting relationships between teachers and their students are now used for learning, educator professional development, and content sharing. Ning for teachers, Learn Central,[69] TeachStreet and other sites are being built to foster relationships that include educational blogs, eportfolios, formal and ad hoc communities, as well as communication such as chats, discussion threads, and synchronous forums. These sites also have content sharing and rating features.

Social networks are also emerging as online yearbooks, both public and private. One such service is MyYearbook which allows anyone from the general public to register and connect. A new trend emerging are private label yearbooks only accessible by students, parents and teachers of a particular school similar to Facebook beginning within Harvard.

Finance applications The use of virtual currency systems inside social networks create new opportunities for global finance. Hub Culture operates a virtual currency Ven used for global transactions among members, product sales[70] and financial trades in commodities and carbon credits. [71] [72] In May 2010, Carbon pricing contracts were introduced to the weighted basket of currencies and commodities that determine the floating exchange value of Ven. The introduction of carbon to the calculation price of the currency made Ven the first and only currency that is linked to the environment.[73]

Medical applications Social networks are beginning to be adopted by healthcare professionals as a means to manage institutional knowledge, disseminate peer to peer knowledge and to highlight individual physicians and institutions. The advantage of using a dedicated medical social networking site is that all the members are screened against the state licensing board list of practitioners.[74] The role of social networks is especially of interest to pharmaceutical companies who spend approximately "32 percent of their marketing dollars" attempting to influence the opinion leaders of social networks.[75] A new trend is emerging with social networks created to help its members with various physical and mental ailments.[76] For people suffering from life altering diseases, PatientsLikeMe offers its members the chance to connect with others dealing with similar issues and research patient data related to their condition. For alcoholics and addicts, SoberCircle gives people in recovery the ability to communicate with one another and strengthen their recovery through the encouragement of others who can relate to their situation. DailyStrength is also a website that offers support groups for a wide array of topics and conditions, including the support topics offered by PatientsLikeMe and SoberCircle. SparkPeople offers community and social networking tools for peer support during weight loss.

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Open source software There are a number of projects that aim to develop free and open source software to use for social networking services. The projects include Anahita Social Engine[77] , Diaspora, Appleseed Project[78] and OneSocialWeb.[79]

In the media • In December 2010, Time Magazine named Facebook CEO Mark Zuckerberg as person of the year.

• The Social Network - a 2010 drama biopic about the origin of Facebook

References • Boyd, Danah; Ellison, Nicole (2007). "Social Network Sites: Definition, History, and Scholarship" [80]. Journal of Computer-Mediated Communication 13 (1).

• Boyd, Danah (2006). "Friends, Friendsters, and MySpace Top 8: Writing Community Into Being on Social Network Sites" [81]. First Monday 11 (12).

• Ellison, Nicole B.; Steinfield, Charles; Lampe, Cliff (2007). "The benefits of Facebook "friends": Exploring the relationship between college students' use of online social networks and social capital" [82]. Journal of Computer-Mediated Communication 12 (4).

• Fraser, Matthew; Dutta, Soumitra (2008). Throwing Sheep in the Boardroom: How Online Social Networking Will Transform Your Life, Work and World [83]. Wiley. ISBN 978-0470740149.

• Mazer, J. P.; Murphy, R. E.; Simonds, C. J. (2007). "I'll See You On "Facebook": The Effects of Computer-Mediated Teacher Self-Disclosure on Student Motivation, Affective Learning, and Classroom Climate" [84] . Communication Education 56 (1): 1–17. doi:10.1080/03634520601009710.

Notes [1] "Nexopia stats on" (http:/ / www. alexa. com/ data/ details/ traffic_details/ nexopia. com). Alexa.com. . Retrieved 2011-03-13.

[2] Bebo (http:/ / www. techcrunch. com/ 2007/ 08/ 20/ windows-live-messaging-coming-to-bebo/ ) - most popular of its kind in UK,(August 2007): TechCrunch website. Retrieved on January 15, 2008.

[3] German Xing Plans Invasion of LinkedIn Turf (http:/ / www. marketingvox. com/ german-xing-plans-invasion-of-linkedin-turf-030727/ ): article from the MarketingVox website.

[4] Elevator Pitch: Why Badoo wants to be the next word in social networking (http:/ / blogs. guardian. co. uk/ digitalcontent/ 2008/ 03/ elevator_pitch_why_badoo_wants. html), Mark Sweney , The Guardian, December 24, 2007 , Accessed March 2008.

[5] Hi5 popular in Europe (http:/ / www. pbs. org/ mediashift/ 2007/ 06/ try_try_againorkut_friendster. html): article from the PBS MediaShift website. Retrieved on January 18, 2008.

[6] "Why Users Love Orkut" (http:/ / usability. about. com/ od/ websiteaudiences/ a/ Orkut. htm) - 55% of users are Brazilian: About.com website. Retrieved on January 15, 2008, [7] The Network Nation by S. Roxanne Hiltz and Murray Turoff (Addison-Wesley, 1978, 1993) [8] Cotriss, David (2008-05-29). "Where are they now: TheGlobe.com" (http:/ / www. thestandard. com/ news/ 2008/ 05/ 29/ where-are-they-now-theglobe-com). The Industry Standard. .

[9] Romm-Livermore, C. & Setzekorn, K. (2008). Social Networking Communities and E-Dating Services: Concepts and Implications‎. IGI Global. p.271 [10] http:/ / jcmc. indiana. edu/ vol13/ issue1/ boyd. ellison. html [11] http:/ / www. longislandpress. com/ 2010/ 09/ 30/ from-friendster-to-myspace-to-facebook-the-evolution-and-deaths-of-social-networks/ [12] (http:/ / www. bnet. com/ videos/ gibby-miller-inventing-the-social-network/ 239462) [13] Knapp, E. (2006). A Parent's Guide to Myspace‎. DayDream Publishers. ISBN 1-4196-4146-8 [14] Steve Rosenbush (2005). News Corp.'s Place in MySpace (http:/ / www. businessweek. com/ technology/ content/ jul2005/ tc20050719_5427_tc119. htm), BusinessWeek, July 19, 2005. (MySpace Page Views figures) [15] "Social graph-iti" (http:/ / www. economist. com/ business/ displaystory. cfm?story_id=9990635): Facebook's social network graphing: article from The Economist's website. Retrieved on January 19, 2008.

[16] comScore. (2007). Social networking goes global. Reston, VA. Retrieved September 9, 2007 (http:/ / www. comscore. com/ press/ release. asp?press=1555) [17] Mackaay, Ejan (1990). "Economic Incentives in Markets for Information and Innovation". Harvard Journal of Law & Public Policy 13 (909): 867–910.

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Social networking service [18] Heylighen, Francis (2007). "Why is Open Access Development so Successful?". In B. Lutterbeck, M. Barwolff, and R. A. Gehring. Open Source Jahrbuch. Lehmanns Media.

[19] Gross, R and Acquisti, A (2005). Information Revelation and Privacy in Online Social Networks (The Facebook case) (http:/ / www. heinz. cmu. edu/ ~acquisti/ papers/ privacy-facebook-gross-acquisti. pdf). Pre-proceedings version. ACM Workshop on Privacy in the Electronic Society (WPES) [20] http:/ / www. mitpressjournals. org/ doi/ pdf/ 10. 1162/ dmal. 9780262524834. 119 [21] A New Generation Reinvents Philanthropy (http:/ / online. wsj. com/ public/ article/ SB118765256378003494. html), Wall Street Journal website.

[22] "Half of employees banned from Facebook at work" (http:/ / www. telegraph. co. uk/ technology/ facebook/ 8506380/ Half-of-employees-banned-from-Facebook-at-work. html). The Daily Telegraph (London). 2011-05-11. .

[23] http:/ / news. searchofficespace. com/ sos-news/ 50-of-british-employers-have-banned-facebook-from-the-office-what-do-you-think. html [24] Search for "e-commerce, social networking" (http:/ / www. google. com/ trends?q=e-commerce,+ social+ networking& ctab=0& geo=all& date=all& sort=1). Google Trends. Accessed 26 October 2009.

[25] MG Siegler Jan 15, 2010 (2010-01-15). "Yelp Enables Check-Ins On Its iPhone App; Foursquare, Gowalla Ousted As Mayors" (http:/ / www. techcrunch. com/ 2010/ 01/ 15/ yelp-iphone-app-4-check-ins/ ). Techcrunch.com. . Retrieved 2011-03-13.

[26] Nimetz, Jody. "Jody Nimetz on Emerging Trends in B2B Social Networking" (http:/ / www. marketing-jive. com/ 2007/ 11/ jody-nimetz-on-emerging-trends-in-b2b. html). Marketing Jive, November 18, 2007. Accessed 26 October 2009.

[27] Liebeskind, Julia Porter, et al. "Social Networks, Learning, and Flexibility: Sourcing Scientific Knowledge in New Biotechnology Firms" (http:/ / www. jstor. org/ pss/ 2635102). Organization Science, Vol. 7, No. 4 (July–August 1996), pp. 428–443.

[28] Carlson, Ben (April 28, 2010). "March 2.0: Success of the National Equality March relied on social media tools" (http:/ / www. mediabullseye. com/ mb/ 2010/ 04/ march-2-0-success-of-the-national-equality-march-relied-on-social-media-tools. html#idc-container).

Media Bullseye. . Retrieved 2010-04-29.

[29] Arabie, Phipps, and Yoram Wind. "Marketing and Social Networks" (http:/ / books. google. com/ books?hl=en& lr=& id=C6juDKDmvCcC& oi=fnd& pg=PR9& dq=social+ networking& ots=Aw9oXw-AtG& sig=CPAZMmPPnAhSZzAu0lh-k4iUXt4#PRA1-PA254,M1). In Stanley Wasserman and Joseph Galaskiewicz, Advances in Social Network Analysis: Research in the Social and Behavioral Sciences. Thousand Oaks, Calif.: Sage Publications, 1994, pp. 254–273. ISBN 0-8039-4302-4 [30] Chambers, Clem. "Murdoch Will Earn a Payday from MySpace" (http:/ / www. forbes. com/ technology/ ebusiness/ 2006/ 03/ 29/ microsoft-myspace-newscorp-in_cc_0330soapbox_inl. html). Forbes, March 30, 2006. Accessed 26 October 2009.

[31] Tynan, Dan. "As Applications Blossom, Facebook Is Open for Business" (http:/ / www. wired. com/ techbiz/ startups/ news/ 2007/ 07/ facebook_platform) Wired, July 30, 2007. Accessed 26 October 2009.

[32] Flor, Nick V. (2000). Web Business Engineering: Using Offline Activities to Drive Internet Strategies. Reading, Mass.: Addison-Wesley.

ISBN 0-201-60468-X; Flor, Nick V. "Week 1: The Business Model Approach to Web Site Design" (http:/ / www. informit. com/ articles/ article. aspx?p=20882). InformIT, March 2, 2001. Accessed 26 October 2009. Description of the autonomous business model used in social networking services.

[33] Social network launches worldwide spam campaign (http:/ / www. e-consultancy. com/ news-blog/ 364182/ social-network-launches-worldwide-spam-campaign. html) E-consultancy.com, Accessed 10 September 2007 [34] Moreno MA, Fost NC, Christakis DA (2008). "Research ethics in the MySpace era". Pediatrics 121 (1): 157–61. doi:10.1542/peds.2007-3015. PMID 18166570.

[35] David Rosenblum (2007). "What Anyone Can Know: The Privacy Risks of Social Networking Sites" (http:/ / www. computer. org/ portal/ web/ csdl/ doi/ 10. 1109/ MSP. 2007. 75). .

[36] Henry Jenkins and Danah Boyd (2006-05-24). "Discussion: MySpace and Deleting Online Predators Act (DOPA)" (http:/ / www. danah. org/ papers/ MySpaceDOPA. html). . Retrieved 2006-05-26.

[37] Susan B. Barnes (2006-09-04). "A privacy paradox: Social networking in the United States" (http:/ / firstmonday. org/ htbin/ cgiwrap/ bin/ ojs/ index. php/ fm/ article/ viewArticle/ 1394/ 1312). .

[38] BBC (2009-03-25). "Social Network Sites 'Monitored'" (http:/ / news. bbc. co. uk/ 1/ hi/ uk_politics/ 7962631. stm). BBC News. . Retrieved 2009-03-25.

[39] "Niet compatibele browser" (http:/ / www. facebook. com/ policy. php?ref=pf). Facebook. . Retrieved 2011-03-13.

[40] boyd, danah. "Why Youth (Heart) Social Network Sites: The Role of Networked Publics in Teenage Social Life" [41] May 22, 2007 12:00AM (2007-05-22). "Fatal MySpace internet hoax mother is charged, Herald Sun, 17 May 2008" (http:/ / www. news. com. au/ heraldsun/ story/ 0,21985,21775032-11869,00. html). News.com.au. . Retrieved 2011-03-13.

[42] "Banned for keeps on Facebook for odd name, Sydney Morning Herald, 24 September 2008" (http:/ / www. smh. com. au/ news/ biztech/ banned-for-keeps-on-facebook-for-odd-name/ 2008/ 09/ 25/ 1222217399252. html). Smh.com.au. 2008-09-25. . Retrieved 2011-03-13.

[43] Enhancing Child Safety and Online Technologies (http:/ / cyber. law. harvard. edu/ pubrelease/ isttf/ ). Internet Safety Technical Task Force, Final Report of the Internet Safety Technical Task Force to the Multi-State Working Group on Social Networking of State Attorneys General of the United States. 2008 (published 31 December 2008). ; Mangu-Ward, Katherine (May 2009). "MySpace = Safe Space". Reason 41 (1): 16.

[44] Wilson, Charles (May 27, 2010). Child porn 'social networking site' busted by feds (http:/ / www. washingtonpost. com/ wp-dyn/ content/ article/ 2010/ 05/ 27/ AR2010052700559. html). Associated Press.

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Social networking service [45] Computer Science Illuminated [46] Boyd, Danah. "Why Youth (Heart) Social Networking Sites: The Role of Networked Publics in Teenage Social Life." Dokutech Eres. Web. <http://eres.ucsc.edu/eres/coursepage.aspx?cid=3840&page=docs#>.

[47] http:/ / firstmonday. org/ htbin/ cgiwrap/ bin/ ojs/ index. php/ fm/ article/ viewArticle/ 1394/ 1312#note4 [48] Derbyshire, David (24 February 2009). "Social websites harm children's brains: Chilling warning to parents from top neuroscientist" (http:/ / www. dailymail. co. uk/ news/ article-1153583/ Social-websites-harm-childrens-brains-Chilling-warning-parents-neuroscientist. html). Daily Mail (London). .

[49] "Mark Nowotarski, "Don't Steal My Avatar! Challenges of Social Network Patents, IP Watchdog, January 23, 2011" (http:/ / ipwatchdog. com/ 2011/ 01/ 23/ donâ t-steal-my-avatar-challenges-of-social-networking-patents/ id=14531/ ). Ipwatchdog.com. . Retrieved 2011-03-13.

[50] "USPTO search on issued patents mentioning “social network”" (http:/ / patft. uspto. gov/ netacgi/ nph-Parser?Sect1=PTO2& Sect2=HITOFF& u=/ netahtml/ PTO/ search-adv. htm& r=0& p=1& f=S& l=50& Query=spec/ "social+ network"& d=PTXT).

Patft.uspto.gov. . Retrieved 2011-03-13.

[51] "Nowotarski, Mark “Reducing Patent Backlog and Prosecution Costs Using PAIR data”, IP Watchdog, August 16, 2010" (http:/ / ipwatchdog. com/ 2010/ 08/ 16/ reducing-patent-backlog-prosecution-costs-using-pair-data/ id=12108/ ). Ipwatchdog.com. . Retrieved 2011-03-13.

[52] Added by Mikk Putk on July 30, 2009 at 6:48am View Videos (2009-07-30). "News 12 “On the Money” interview of Mark Nowotarski, July 30, 2009" (http:/ / ipestonia. ning. com/ video/ patents-on-social-media). Ipestonia.ning.com. . Retrieved 2011-03-13.

[53] "theodp Slashdot.org 6/16/2010" (http:/ / yro. slashdot. org/ story/ 10/ 06/ 16/ 2233230/ USPTO-Lets-Amazon-Patent-the-Social-Networking-System?from=twitter). Yro.slashdot.org. . Retrieved 2011-03-13.

[54] Forbes. http:/ / blogs. forbes. com/ docket/ 2010/ 06/ 17/ amazon-secures-patent-for-social-networking-system/ .

[55] US Patent and Trademark Office (http:/ / patft. uspto. gov/ netacgi/ nph-Parser?Sect1=PTO1& Sect2=HITOFF& d=PALL& p=1& u=/ netahtml/ PTO/ srchnum. htm& r=1& f=G& l=50& s1=7,739,139. PN. & OS=PN/ 7,739,139& RS=PN/ 7,739,139) Patent number 7,739,139 [56] "Network World" (http:/ / www. networkworld. com/ news/ 2010/ 061710-amazon-social-network-patent. html). Network World. .

Retrieved 2011-03-13.

[57] "MySpace exposes sex predators" (http:/ / www. news. com. au/ heraldsun/ story/ 0,21985,,00. html), use of its content in the courtroom: Herald and Weekly Times (Australia) website. Retrieved on January 19, 2008.

[58] "Getting booked by Facebook" (http:/ / www. jsonline. com/ story/ index. aspx?id=670380), courtesy of campus police: Milwaukee Journal Sentinel website. Retrieved on January 19, 2008.

[59] "Police use Facebook to identify weapon carriers" (http:/ / www. journal-online. co. uk/ article/ 5410-police-use-facebook-to-identify-weapon-carriers) The Journal (Edinburgh) website. Retrieved on May 11, 2009 [60] "Government Agencies Establishing Presence on Social-Networking Sites" (http:/ / www. itbusinessedge. com/ topics/ reader. aspx?oss=37848). Itbusinessedge.com. . Retrieved 2011-03-13.

[61] "OSTP Press Release Announcing Review (pdf, 50k)" (http:/ / www. nasa. gov/ pdf/ 358006main_OSTP Press Release. pdf) (PDF). .

Retrieved 2011-03-13.

[62] "Latest LinkedIn Facts" (http:/ / press. linkedin. com/ about). Press.linkedin.com. . Retrieved 2011-03-13.

[63] MySpace, Facebook Add Opportunity for Love, Trouble to Online Dating (http:/ / www. foxnews. com/ story/ 0,2933,396461,00. html), FOXNews.com website.

[64] MySpace Adds a Security Monitor (http:/ / www. npr. org/ templates/ story/ story. php?storyId=5336688), NPR.com website.

[65] Online Dating: Can Social Networks Cut In? (http:/ / www. internetnews. com/ ec-news/ article. php/ 3659911), internetnews.com website.

[66] Online Dating vs. Social Networking – Which Will Emerge as Premier Matchmaker? (http:/ / localtechwire. com/ business/ local_tech_wire/ opinion/ story/ 2449164/ ), WRAL.com website.

[67] Social networks vs. dating sites Commentary: Fragmenting may save online dating sites (http:/ / www. marketwatch. com/ news/ story/ story. aspx?guid={4640E6FF-17B8-40D5-901C-098EE74B03DD}), marketwatch.com website.

[68] Seeking Love Around The Web (http:/ / www. forbes. com/ 2007/ 12/ 20/ online-dating-love-tech-personal-cx_wt_1221dating. html), Forbes.com website.

[69] learncentral.org [70] Wall street journal blog article about Ven (http:/ / blogs. wsj. com/ economics/ 2009/ 09/ 09/ the-currency-revolution/ ) [71] http:/ / www. finextra. com/ news/ fullstory. aspx?newsitemid=22475| [72] http:/ / blog. americancarbonregistry. org/ redd/ american-carbon-registry-offsets-retired-ven-carbon-transaction/ [73] http:/ / www. hubculture. com/ groups/ 237/ news/ 486/ [74] Social Networking: Now Professionally Ready (http:/ / www. primarypsychiatry. com/ aspx/ articledetail. aspx?articleid=975), PrimaryPsychiatry.com website.

[75] Social Networks Impact the Drugs Physicians Prescribe According to Stanford Business School Research (http:/ / www. medadnews. com/ News/ index. cfm?articleid=424455), Pharmalive.com website.

[76] Comprehensive listing of medical applications using social networking (http:/ / www. doseofdigital. com/ healthcare-pharma-social-media-wiki/ ) via Dose of Digital [77] Anahita Social Engine Project. "The Anahita Social Engine Framework and Platform" (http:/ / www. anahitapolis. com). . . Retrieved 2011-01-18.

39

Social networking service [78] The Appleseed Project. "The Appleseed Project - Open Source Social Networking" (http:/ / opensource. appleseedproject. org).

Opensource.appleseedproject.org. . Retrieved 2011-03-13.

[79] "Creating a free, open, and decentralized social networking platform" (http:/ / onesocialweb. org/ ). OneSocialWeb. . Retrieved 2011-03-13.

[80] http:/ / jcmc. indiana. edu/ vol13/ issue1/ boyd. ellison. html [81] http:/ / www. firstmonday. org/ issues/ issue11_12/ boyd/ index. html [82] http:/ / jcmc. indiana. edu/ vol12/ issue4/ ellison. html [83] http:/ / books. google. com/ ?id=SP92NwAACAAJ [84] http:/ / www. informaworld. com/ smpp/ ftinterface~content=a769651179~fulltext=713240930

Further reading • Alemán, Ana M. Martínez; Wartman, Katherine Lynk, "Online social networking on campus: understanding what matters in student culture" (http://books.google.com/books?id=GH4KOM3MS-sC&printsec=frontcover), New York and London : Routledge, 1st edition, 2009. ISBN 0-415-99019-X • Barham, Nick, Disconnected: Why our kids are turning their backs on everything we thought we knew, 1st ed., Ebury Press, 2004. ISBN 0-09-189586-3 • Baron, Naomi S., Always on : language in an online and mobile world (http://books.google.com/ books?id=X8-gaJM6NUIC&printsec=frontcover), Oxford ; New York : Oxford University Press, 2008. ISBN 978-0-19-531305-5 • Cockrell, Cathy, "Plumbing the mysterious practices of 'digital youth': In first public report from a 'seminal' study, UC Berkeley scholars shed light on kids' use of Web 2.0 tools" (http://www.berkeley.edu/news/media/ releases/2008/04/28_digitalyouth.shtml), UC Berkeley News, University of California, Berkeley, NewsCenter, 28 April 2008 • Kelsey, Todd (2010), Social Networking Spaces: From Facebook to Twitter and Everything In Between (http:// books.google.ca/books?id=1EgTu8fFMJgC&lpg=PP1&ots=HUuksBAE9m&dq=Social Networking Spaces: From Facebook to Twitter and Everything In Between&pg=PP1#v=onepage&q&f=true), Springer-Verlag, ISBN 9781430225966 • Davis, Donald Carrington, "MySpace Isn't Your Space: Expanding the Fair Credit Reporting Act to Ensure Accountability and Fairness in Employer Searches of Online Social Networking Services" (http://www.law.ku. edu/publications/journal/pdf/v16n2/davis.pdf), 16 Kan. J.L. & Pub. Pol'y 237 (2007).

• Else, Liz; Turkle, Sherry. "Living online: I'll have to ask my friends" (http://web.mit.edu/sturkle/www/ pdfsforstwebpage/ST_Living Online.pdf), New Scientist, issue 2569, 20 September 2006. (interview) • Glaser, Mark, Your Guide to Social Networking Online (http://www.pbs.org/mediashift/2007/08/ digging_deeperyour_guide_to_so_1.html)," PBS MediaShift, August 2007 • Powers, William, Hamlet’s Blackberry : a practical philosophy for building a good life in the digital age, 1st ed., New York : Harper, 2010. ISBN 978-0-06-168716-7 • Video on the History of social networks by WikiLecture (http://wikilecture.org/Social_network_service)

40

Opportunity cost

Opportunity cost Opportunity cost is the cost of any activity measured in terms of the best alternative forgone. It is the sacrifice related to the second best choice available to someone who has picked among several mutually exclusive choices.[1] It is a key concept in economics. It has been described as expressing "the basic relationship between scarcity and choice."[2] The notion of opportunity cost plays a crucial part in ensuring that scarce resources are used efficiently.[3] Thus, opportunity costs are not restricted to monetary or financial costs: the real cost of output forgone, lost time, pleasure or any other benefit that provides utility should also be considered opportunity costs.

The concept of an opportunity cost was first developed by John Stuart Mill.[4]

Opportunity costs in consumption Opportunity cost is assessed in not only monetary or material terms, but also in terms of anything which is of value.

For example, a person who desires to watch each of two television programs being broadcast simultaneously, and does not have the means to make a recording of one, can watch only one of the desired programs. Therefore, the opportunity cost of watching Dallas could be not enjoying the other program (e.g. Dynasty). Of course, if an individual records one program while watching the other, the opportunity cost will be the time that the individual spends watching one program versus the other. In a restaurant situation, the opportunity cost of eating steak could be trying the salmon. For the diner, the opportunity cost of ordering both meals could be twofold - the extra $20 to buy the second meal, and his reputation with his peers, as he may be thought gluttonous or extravagant for ordering two meals. A family might decide to use a short period of vacation time to visit Disneyland rather than doing household improvements. The opportunity cost of having happier children could therefore be a remodeled bathroom.

In environmental protection, the opportunity cost is also applicable. This has been demonstrated in the legislation that required the carcinogenic aromatics (mainly reformate) to be largely eliminated from gasoline. Unfortunately, this required refineries to install equipment at a cost of hundreds of millions of dollars - and pass the cost to the consumer. The absolute number of cancer cases following from exposure to gasoline, however, is low, estimated a few cases per year in the U.S. Thus, the decision to legally require less aromatics has been criticized on the grounds of opportunity cost: the hundreds of millions spent on process redesign could have been spent on other, more fruitful ways of reducing deaths caused by cancer or automobiles.[5] These actions (or strictly, the best one of them) are the opportunity cost of reduction of aromatics in gasoline.

Opportunity costs in production Opportunity costs may be assessed in decision-making process of production. If the workers on a farm can produce either 1 million pounds of wheat or 2 million pounds of barley, then the opportunity cost of producing 1 pound of wheat is the 2 pounds of barley forgone. Firms would make rational decisions by weighing the sacrifices involved.

Explicit costs Explicit costs are opportunity costs that involve direct monetary payment by producers. The opportunity cost of the factors of production not already owned by a producer is the price that the producer has to pay for them. For instance, a firm spends $100 on electrical power consumed, the opportunity cost is $100. The firm has sacrificed $100, which could have been spent on other factors of production.

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Opportunity cost

Implicit costs Implicit costs are by contrast, the opportunity costs that involve only factors of production that a producer already owns. They are equivalent to what the factors could earn for the firm in alternative uses, either operated within the firm or rent out to other firms.

Evaluation The consideration of opportunity costs is one of the key differences between the concepts of economic cost and accounting cost. Assessing opportunity costs is fundamental to assessing the true cost of any course of action. In the case where there is no explicit accounting or monetary cost (price) attached to a course of action, or the explicit accounting or monetary cost is low, then, ignoring opportunity costs may produce the illusion that its benefits cost nothing at all. The unseen opportunity costs then become the implicit hidden costs of that course of action.

Note that opportunity cost is not the sum of the available alternatives when those alternatives are, in turn, mutually exclusive to each other. The opportunity cost of the city's decision to build the hospital on its vacant land is the loss of the land for a sporting center, or the inability to use the land for a parking lot, or the money which could have been made from selling the land, as use for any one of those purposes would preclude the possibility to implement any of the other. It is also the cost of the forgone products after making a choice.

However, most opportunities are difficult to compare. Opportunity cost has been seen as the foundation of the marginal theory of value as well as the theory of time and money. In some cases it may be possible to have more of everything by making different choices; for instance, when an economy is within its production possibility frontier.

In microeconomic models this is unusual, because individuals are assumed to maximise utility, but it is a feature of Keynesian macroeconomics. In these circumstances opportunity cost is a less useful concept.

In a 2005 survey at the annual meeting of American Economic Association, 21.6% of professional economists surveyed chose the correct answer to a question on opportunity cost. The researchers later asked a similar but differently phrased question, to which a majority of the economists surveyed gave an incorrect answer. When the researchers posed the original question to a larger group of college students, 7.4% of those who had taken a course in economics answered correctly, compared to 17.2% of those who had never taken one. The researchers, Paul J. Ferraro and Laura O. Taylor of Georgia State University, labeled the results "a dismal performance from the dismal science."[6]

References [1] "Opportunity Cost" (http:/ / www. investopedia. com/ terms/ o/ opportunitycost. asp). Investopedia.com:. . Retrieved 2010-09-18.

[2] James M. Buchanan (2008). "Opportunity cost" (http:/ / www. dictionaryofeconomics. com/ search_results?q=opportunity+ cost& edition=current& button_search=GO). Second Edition. The New Palgrave Dictionary of Economics Online. . Retrieved 2010-09-18.

[3] "Opportunity Cost" (http:/ / www. economist. com/ research/ Economics/ alphabetic. cfm?letter=O#opportunitycost). Economics A-Z. The Economist. . Retrieved 2010-09-18.

[4] George Stigler (November 1955). "The Nature and Role of Originality in Scientific Progress". Economica XXII. [5] Harold A. Wittcoff, Bryan G. Reuben, Jeffery S. Plotkin. Industrial Organic Chemicals. Wiley 2004.

[6] Robert H Frank (2005-09-01). "The Opportunity Cost of Economics Education" (http:/ / www. nytimes. com/ 2005/ 09/ 01/ business/ 01scene. html?_r=2). New York Times. . Retrieved 201009-18.

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Opportunity cost

External links â&#x20AC;˘ The Opportunity Cost of Economics Education (http://www.nytimes.com/2005/09/01/business/01scene. html) by Robert H. Frank â&#x20AC;˘ Opportunity Cost Example & Analysis (http://www.youtube.com/watch?v=ezOdQUzLVAo)

Acceptable use policy An acceptable use policy (AUP; also sometimes acceptable usage policy or Fair Use Policy) is a set of rules applied by the owner/manager of a network, website or large computer system that restrict the ways in which the network site or system may be used. AUP documents are written for corporations,[1] businesses, universities,[2] schools,[3] internet service providers,[4] and website owners[5] often to reduce the potential for legal action that may be taken by a user, and often with little prospect of enforcement.

Acceptable Use Policies are an integral part of the framework of information security policies; it is often common practice to ask new members of an organization to sign an AUP before they are given access to its information systems. For this reason, an AUP must be concise and clear, while at the same time covering the most important points about what users are, and are not, allowed to do with the IT systems of an organization. It should refer users to the more comprehensive security policy where relevant. It should also, and very notably, define what sanctions will be applied if a user breaks the AUP. Compliance with this policy should, as usual, be measured by regular audits.

Terminology AUP documents are similar to and often doing the same job as a document labelled Terms of Service for example, as used by Google Gmail [6] and Yahoo! [7], although not in every instance, as in the case of IBM.com [8] where the Terms of Use is about the way in which IBM presents the site for you, and how they will interact with you using the site with little to no instruction as to how you, the user, will use the site.

In some cases, AUP documents are named Internet and E-mail policy [9], Internet AUP, or Network AUP and also Acceptable IT Use Policy [10]. These documents, even though named differently, largely provide policy statements as to what behaviour is acceptable from users of the local network/Internet connected via the local network.

Common elements of AUP statements In general, AUP statements/documents often begin with a statement of the philosophy [11] of the sponsoring organisation and intended reason as to why Internet use is offered to the users of that organisation's network. For example, the sponsoring organisation adopts a philosophy of self-regulation and offers the user connection to the local network and also connection to the Internet providing that the user accepts the fact she/he is going to be personally responsible for actions taken when connected to the network or Internet. This may mean that the organisation is not going to provide any warning system should the user contravene policy, maintaining that it is up to the user to know when his/her actions are in violation of policy. Often Acceptable Use Policy documents provide a statement about the use of the network and/or Internet and its uses and advantages [12] to the business, school or other organisation sponsoring connection to the Internet. Such a statement may outline the benefit of email systems, ability to gain information from websites, connection with other people through the use of instant messaging, and other similar benefits of various protocols including the relatively new VoIP services.

The most important part of an AUP document is the code of conduct [13] governing the behaviour of a user whilst connected to the network/Internet. The code of conduct may include some description of what may be called netiquette which includes such items of conduct as using appropriate/polite language while online, avoiding illegal activities, ensuring that activities the user may embark on should not disturb or disrupt any other user on the system,

43

Acceptable use policy and caution not to reveal personal information that could be the cause of identity theft.

Most AUP statements outline consequences of violating [14] the policy. Such violations are met with consequences depending on the relationship of the user with the organisation. Common actions that schools and universities take is to withdraw the service to the violator and sometimes if the activities are illegal the organization may involve appropriate authorities, such as the local police. Employers will at times withdraw the service from employees, although a more common action is to terminate employment when violations may be hurting the employer in some way, or may compromise security. Earthlink [14], an American Internet service provider has a very clear policy relating to violations of its policy. The company identifies six levels of response to violations: • • • • • •

issue warnings: written or verbal suspend the Member's newsgroup posting privileges suspend the Member's account terminate the Member's account bill the Member for administrative costs and/or reactivation charges bring legal action to enjoin violations and/or to collect damages, if any, caused by violations.

Central to most AUP documents is the section detailing unacceptable uses of the network, as displayed in the University of Chicago AUP [15]. Unacceptable behaviours may include creation and transmission of offensive, obscene, or indecent document or images, creation and transmission of material which is designed to cause annoyance, inconvenience or anxiety, creation of defamatory material, creation and transmission that infringes copyright of another person, transmission of unsolicited commercial or advertising material and deliberate unauthorised access to other services accessible using the connection to the network/Internet. Then there is the type of activity that uses the network to waste time, as indicated in SurfControl's advice on writing AUPs [16], of technical staff to troubleshoot a problem for which the user is the cause, corrupting or destroying other user's data, violating the privacy of others online, using the network in such a way that it denies the service to others, continuing to use software or other system for which the user has already been warned about using, and any other misuse of the network such as introduction of viruses.

Disclaimers are often added in order to absolve an organisation from responsibility under specific circumstances. For example, in the case of Anglia Ruskin University [17] a disclaimer is added absolving the University for errors or omissions or for any consequences arising from the use of information contained on the University website. While disclaimers may be added to any AUP, disclaimers are most often found on AUP documents relating to the use of a website while those offering a service fail to add such clauses. PsychologyUK [18], a magazine forum site, includes the type of disclaimer that can be used in an AUP for a website or online service of some type.

Particularly when an AUP is written for a college or school setting, AUPs remind students (or when in the case of a company, employees) that connection to the Internet, or use of a website, is a privilege, as demonstrated in the Loughborough University's Janet Service AUP [10] and not a right. Through emphasising this "privilege" aspect, Northern Illinois University [19] then make the connection that any abuse of that privilege can result in legal action from the University.

In a handbook for writing AUP documents [12], the Virginia Department of Education indicate that there are three other areas needing to be addressed in an AUP: • a statement that the AUP is in compliance with state and national telecommunication rules and regulations • a statement regarding the need to maintain personal safety and privacy while accessing the Internet • a statement regarding the need to comply with Fair Use Laws and other copyright regulations while accessing the Internet Through a cursory reading of AUP statements found by a Google Search [20] the variation of the inclusion of these items in AUP documents is highly variable. However, those statements in a school or university setting are more likely to include a statement to address at least the "personal safety" issue.

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Acceptable use policy

Enforceability 6.3 This Policy shall be governed by the laws of England and the parties submit to the exclusive jurisdiction of the Courts of England and Wales.

And of course with the ever widening of the number of jurisdictions covered by the Internet, the AUP document needs to indicate the jurisdiction, meaning the laws that are applicable and govern the use of an AUP. Even if a company is only located in one jurisdiction and the AUP applies to only its employees naming the jurisdiction saves difficulties of interpretation should legal action be required to enforce its statements.

References [1] "IS.SEC.005" (http:/ / google. com/ search?q=cache:hBXqLlQN39IJ:ec. hcahealthcare. com/ CPM/ ISSEC005. doc+ "internet+ policy"+ site:hcahealthcare. com& hl=en& ct=clnk& cd=1& gl=us). Hospital Corporation of America. 2007-12-01. . Retrieved 2008-12-13.

[2] "Policy on Acceptable Use of Electronic Resources" (http:/ / www. upenn. edu/ computing/ policy/ aup. html). University of Pennsylvania. .

Retrieved 2008-12-13.

[3] "2008-2009 Code of Student Conduct" (http:/ / www. ccps. k12. fl. us/ Downloads/ COSC0809. pdf) (pdf). Charlotte County Public Schools. . Retrieved 2008-12-13.

[4] "EMBARQ ACCEPTABLE USE POLICY & VISITOR AGREEMENT" (http:/ / www2. embarq. com/ legal/ acceptableuse. html). Embarq.

2006-10-20. . Retrieved 2008-12-13.

[5] "MySpace.com Terms of Use Agreement" (http:/ / www. myspace. com/ index. cfm?fuseaction=misc. terms). Myspace. 2008-02-28. .

Retrieved 2008-12-13.

[6] http:/ / mail. google. com/ mail/ help/ terms_of_use. html [7] http:/ / info. yahoo. com/ legal/ us/ yahoo/ utos/ utos-173. html [8] http:/ / www. ibm. com/ legal/ us/ [9] http:/ / www. visiongateway. net/ support/ downloads/ document/ AUP%20-%20Employee. pdf [10] http:/ / www. lboro. ac. uk/ computing/ policies/ loughborough-aup. html [11] http:/ / www. solis. co. uk/ aup/ index [12] http:/ / www. pen. k12. va. us/ VDOE/ Technology/ AUP/ home. shtml [13] http:/ / title3. sde. state. ok. us/ technology/ aup. htm [14] http:/ / www. earthlink. net/ about/ policies/ use. faces [15] http:/ / nsit. uchicago. edu/ policies/ eaup/ [16] http:/ / www. surfcontrol. com/ uploadedfiles/ AUP_Booklet_10011_uk. pdf [17] http:/ / www. anglia. ac. uk/ ruskin/ en/ home/ tools/ disclaimer. html [18] http:/ / www. psychologyuk. co. uk/ forum/ faq. php?faq=aup#faq_forum_disclaimer [19] http:/ / www. niu. edu/ aup/ [20] http:/ / www. google. co. uk/ search?q=acceptable+ use+ policy& sourceid=navclient-ff& ie=UTF-8& rlz=1B3GGGL_enAU213AU213

External links • Responsible ISP Acceptable Use Policies (http://www.spamhaus.org/aups.html) on SpamHaus • Critiquing Acceptable Use Policies (http://www.io.com/~kinnaman/aupessay.html) by Dave Kinnaman • Virginia Department of Education Handbook for writing AUP documents (http://www.pen.k12.va.us/VDOE/ Technology/AUP/home.shtml)

45

Article Sources and Contributors

Article Sources and Contributors Computer-mediated communication Source: http://en.wikipedia.org/w/index.php?oldid=429103986 Contributors: 16@r, Aaron Kauppi, Ageekgal, Ahoerstemeier, Alex Kosorukoff, Allanjeong, Andrewpmk, Angela, Art LaPella, Beoram, Betsythedevine, Blanchardb, Bluemask, CJLL Wright, Can't sleep, clown will eat me, Cate, Ccacsmss, Ceyockey, Charles Matthews, Chinhsi, Conan, DARTH SIDIOUS 2, DVD R W, Docu, Ebyabe, Eclipsed, Ehheh, Elainecs, Elamee, EmilySTS, Excirial, Fischbuerger, Frecklefoot, Frehley, Froofroo7, Funnybunny, Glenn, Gul52470, Gwernol, Henersforlife2012, Higbvuyb, Iapetus, Izvora, J.delanoy, JForget, JaGa, Jaedz, Janarius, Jeroen Coumans, Jlo08c, Joseph Solis in Australia, Jossi, Kmm3198, Lkinkade, Longhairandabeard, MBisanz, MCG, Malerin, Mark Elliott, Mazarin07, Mcc101s2, Metonym, Michael Hardy, Mindmatrix, Miquonranger03, Morrismas214, MrOllie, NerdyScienceDude, Nikai, Ntennis, NuclearWarfare, Otisjimmy1, PauliRekola, Peterl, Peyronnin, Pierre cb, Plustgarten, Ponyo, RL0919, Robchurch, Roquentin, RossPatterson, Rsk26, SEWilco, ST47, Savidan, Somertime, Staffwaterboy, Stubblyhead, SymlynX, THEN WHO WAS PHONE?, The Tarr Steps Troll, Tide rolls, Tikiwont, Tom harrison, Tyli2000, UALR Student, VCHunter, Versus22, Viensanity, WikipedianYknOK, Wmahan, Woodbridge123, ZeroOne, Zsinj, 193 anonymous edits Email Source: http://en.wikipedia.org/w/index.php?oldid=429120664 Contributors: 100110100, 16@r, 194.236.5.xxx, 228086, 2D, 7, A More Perfect Onion, A purple wikiuser, A. B., Abkovalenko, AdSR, Adw2000, Aesopos, Aff123a, Agather, Agent2693, Agheefner, Ahoerstemeier, AlainV, Alan Liefting, Alanpratt05, Alansohn, Ale2006, AlexWaelde, Alexius08, Alexjohnc3, Aliza250, Allynnc, Alphathon, Amire80, Amniarix, Anastrophe, Anaxial, Andareed, Andrejj, Andrew Kelly, Andrzej P. 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Article Sources and Contributors Khym Chanur, Kwub, Lisbk, Luckyz, Maparyetal, Nick Wilson, Omicronpersei8, PCHS-NJROTC, Pikiwyn, Poccil, Profcolle, ProveIt, Radiosband, SD5, Salamurai, Scarian, Shimgray, Stifle, Template namespace initialisation script, Tempodivalse, The Thing That Should Not Be, Theresa knott, ThinkBlue, Timo Honkasalo, WJetChao, Wigbold, Woohookitty, Yettie0711, Î&#x201D;, 119 anonymous edits

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Image Sources, Licenses and Contributors File:@@@.svg Source: http://en.wikipedia.org/w/index.php?title=File:@@@.svg License: Public Domain Contributors: User:Yug File:email.svg Source: http://en.wikipedia.org/w/index.php?title=File:Email.svg License: GNU Free Documentation License Contributors: Original uploader was Yzmo at en.wikipedia Image:Pidgin 2.0 contact window.png Source: http://en.wikipedia.org/w/index.php?title=File:Pidgin_2.0_contact_window.png License: unknown Contributors: Pidgin team Image:Unix talk screenshot 01.png Source: http://en.wikipedia.org/w/index.php?title=File:Unix_talk_screenshot_01.png License: GNU General Public License Contributors: Fluteflute, Porao, Shooke, StuartBrady, Sven Image:Pidgin Screenshot Ubuntu.png Source: http://en.wikipedia.org/w/index.php?title=File:Pidgin_Screenshot_Ubuntu.png License: GNU General Public License Contributors: Original uploader was Uberushaximus at en.wikipedia File:Soc-net-paten-growth-chart.png Source: http://en.wikipedia.org/w/index.php?title=File:Soc-net-paten-growth-chart.png License: Creative Commons Attribution-Sharealike 3.0 Contributors: Mark Nowotarski

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