One of the best explanations about the functioning of the PageRank by Google is at:(http://www.webworkshop.net/pagerank.html) Google’s PageRank Explained and how to make the most of it, written by Phil Craven, author of Google’s PageRank Calculator. http://www.webworkshop.net/pagerank_calculator.php3
An article on PCWorld the qualities of other search engines: Beyond Google: Web is so full of useful info that no search engine can find it all.
http://www.pcworld.com/article/id.114725-page.1/article.html
About the multitude of specialty sites deliver shopping advice, reference databases, leisure-time ideas, and more fast, written by Laurianne McLaughlin.
A set of useful tricks to take advantage of search engines may be found at: Internet Librarian: 30 Search Tips in 40 Minutes, in mamamusings http://mamamusings.net/archives/2003/11/03/more by Elizabeth Lane Lawley.
A resource on documenting and search specialized engines, although not too up to date, may be found at: Portal de Buscadores. http://mccd.udc.es/orihuela/voz/