How do search engine algorithm's work?

google's page ranking system is an iterative algorithm that will continue to search for pages that link back to a particular page (Tn) and then rank it PR(A) based upon the number of links. (Brin/Page, 1998) PR(A) = (1-d) + d (PR(T1)/C(T1) + ... + PR(Tn)/C(Tn)) google.html,">http://infolab.stanford.edu/~backrub/google.html, Although the current version of PageRanking used by google is now called PigeonRank, which they believe is faster than machine-based algorithms. http://www.google.com/technology/pigeonrank.html