Web Clustering Websites

Their document clustering and meta-search software automatically categorizes search results on-the-fly into hierarchical clusters.

A search results clustering framework. Includes clustering components and a stand-alone meta search component.

Clusters results from major search engines, associates words that appear in previous searches, and keeps a local cache of all the results you click on in a searchable database. It helps keep track of what you find on the web. [Windows, UNIX, Linux and Mac OSX.]

A metasearch clustering engine for Web, Books, News.