Page Rank(PR) Algorithm

PageRank is a registered trademark and patented by Google on January 9, 1999 which protects a family of algorithms used to assign a numerical relevance of the documents (or web pages) indexed by a search engine. Its properties are discussed by experts in search engine optimization. The PageRank system is used by the popular Google search engine to help you determine the importance or relevance of a page. It was developed by the founders of Google, Larry Page and Sergey Brin at Stanford University.

The initial PageRank algorithm where their creators presented the prototype of Google: "The Anatomy of a Large-Scale Hypertextual Web Search Engine":

PR (A) = (1 - d) + d (PR (T1) / C (T1) + ... + PR (Tn) / C (Tn)



Where PR (A) is the PageRank of a page; PR (Ti) is the PageRank of pages that link to you A, C (Ti) is the number of outbound links on the page you; d is a variable factor which can be between 0 and 1.

PageRank relies on the democratic nature of the web by using its vast link structure as an indicator of the value of a specific page. Google interprets a link in a page A to page B as a vote, by page A, for page B. But Google looks beyond the volume of votes, or links a page receives and also analyzes the page that casts the vote. Votes cast by pages considered "important" worth more, and help to make other pages "important". The PageRank of a page is defined recursively and depends on the number and PageRank of all pages that link.