Google PageRank & what you need to know about it

Google PageRank: What Do We Know About It? – Smashing Magazine

Everybody is using it, but (almost) nobody really knows, how it works. Google PageRank is probably one of the most important algorithms ever developed for the Web. With billions of existing pages and millions of pages generated every day, the search issue in the Web is more complex than you probably think it is. PageRank, only one of hunderds of factors used by Google to determine best search results, helps to keep our search clean and efficient. But how is it actually done?