What is back link?

[therapy]

Search engines often use the number of backlinks that a website has as one of the most important factors for determining that website's search engine ranking, popularity and importance. Google's description of their PageRank system, for instance.
Websites often employ various search engine optimization techniques to increase the number of backlinks pointing to their website. Some methods are free for use by everyone whereas some methods like linkbaiting requires quite a bit of planning and marketing to work. Some websites stumble upon "linkbaiting" naturally; the sites that are the first with a tidbit of 'breaking news' about a celebrity are good examples of that. When "linkbait" happens, many websites will link to the 'baiting' website because there is information there that is of extreme interest to a large number of people.