if you type into google's search engine the question "how does google work?",
google itself offers a curious explanation:
PigeonRank. according to this obvious joke, google uses clusters of trained pigeons to "compute the relative value of web pages faster than human editors or machine-based algorithms".
pigeons, they tell us, can spot minute differences between web pages and will peck when a relevant result appears on the screen.
pages with more pecks move to the top of the list. google assures us that the pigeons are well treated and not overworked.