Just type in a few keywords to search for, and this demo software/research project will search through the NetLibrary e-book collection for matches and arrange the results by Dewey Decimal number, color coded by how many of the hits are in each of Dewey's main categories. If you only get hits in one of the major categories of Dewey, it'll automatically open up the next level(s) of categories (ditto for the second level to the third), and when you select a category in the third level, it lists the books in that category that matched your search.
From the average Joe's perspective, it's a quick way of taking anything up to a Googleplex of hits and sorting them into more managable categories before presenting them to the searcher, by grouping similar things together and arranging those groups in a logical order. It's also a potentially interesting way to teach people how the Dewey Decimal system works. (Gosh, maybe those numbers aren't so random after all! -grin-)
From the librarian's perspective, it's an interesting way of showing the difference between a subject (what you searched for), and a discipline (how the Dewey system is arranged). (Try searching for "gold", "stem cells", "police", or "HTML" and looking at how the results are broken down.) It also demonstrates the practical value of my job-- the sort of stuff I do isn't necessarily all that different from someone working at Google, AltaVista, or Yahoo, and really can make it easier for you to find the information you're looking for.
Feudalism: Serf & Turf