The $25B Eigenvector
For a little insight as to why Google has the top search engine around, one needs look no further than the linear algebra that lies just below the surface. With a concept called PageRank, they rank pages based on the number of links to them, in a democracy of the internet, where each link is a vote. It isn’t a perfect democracy, though, as more important sites (those with more links toward them) have greater weight given their links to other sites.
You can read a nice paper on the details of the Google engine at The $25B Eigenvector. Also, the author has a page where you can download Maple and Mathematica workbooks that demonstrate the basic principles at http://www.rose-hulman.edu/~bryan/google.html.