From Maxine - A rather amusing explanation of how Google determines which pages are listed first when you do a search. Suffice to say it involves PCs - pigeon clusters.
Librarians and other information mavens have long wondered about Google's relevancy algorithms, which Google regards as a trade secret. We like to know how to make our search strategies as efficient as possible, and knowing how the search engine works would obviously be useful, but as a commercial enterprise, Google doesn't want to help people 'game' the system. So this explanation is meant to be funny, but at the same time, it is twitting their critics.