The Philosophy of PageRank
PageRank relies on the uniquely democratic nature of the web by using its vast link structure as anindicator of an individual page's value. In essence, Google interprets a linkfrom page A to page B as a vote, by page A, for page B. But, Google looks at more than thesheer volume of votes, or links a page receives; it also analyzes the page thatcasts the vote. Votes cast by pages that are themselves "important"weigh more heavily and help to make other pages "important."
PageRank Algorithm
PR(A) : PageRank of page A
L(A) : The number of links going out of page A
d : damping factor