Websites today are more complex in comparison to the simple HTML based websites that were so common in the early periods. Today programmers use PHP or ASP technologies to create complex, database driven websites. In order to protect data they also put in measures of protection and techniques to prevent attempts at data retrieval. Ecommerce sites employ techniques to create data on the fly, which means data is presented on the screen in response to requests from users. Then there are sites that require a log in or registration. There are other measures of protection such as keeping an automatic watch on attempts by users from an IP address to access more than the usual amount of data those results in the IP address being blocked. Websites are smarter these days than they used to be because website owners value their data and do not want it to be misused.
If website owners are smart and take steps to protect data and prevent access or retrieval, then there is always a workaround to such measures. People who need data on a regular basis must use these smart techniques one of which is an online data extractor to search for, find and retrieve information they need. Given the complexity of today’s websites and the protection measures in place, scraping data from websites is both an art and science. Firstly, one must know about websites that are likely to yield the required data. Then one must know the terminology or the keywords used in their websites. This requires some intuition and some knowledge. The science part consists of using technology to tunnel into sites and go past barriers in order to harvest data and then compile it into a usable format. Anyone with knowledge of programming and scripting can create scripts to automate the task of web crawling and data harvesting. A better and easier way is to use a ready to use software designed expressly for this purpose.