Xan has a good post today exploring the world of TDT - Topic Detection research. We've been trying to work on something quick and dirty that automatically classifies a web page into a hierarchical category structure based on the key terms and phrases we've found to be common in that topic area. We've had no success, but maybe some of Xan's links can help.

Does anyone know of a good topic detection tool other than Google's simplistic site-flavored tool?