The priority given to the placement of a link on the results page of a Web search. For example, Google's PageRank system, named after co-founder Larry Page, classifies a site based on the number of links that point to it from other sites (the "backlinks"). The concept is that if very prominent sites link to a site, the site has greater value. The more popular the backlink sites themselves are, the higher the ranking as well. In addition to Google's PageRank, the content and organization of the pages on the site are criteria used in the page ranking algorithm. Google claims its algorithm uses more than 200 factors to determine the value of a page. The amount of buzz on social media also plays an important part. The Algorithm Changes Because countless websites are laden with unnecessary content in order to boost their ranking, the search engine formulas are often changed to prevent deceptive content from achieving permanent high ranks. See link juice, search engine optimization, Google bomb and social bookmarking site.