TalkDigger is a WEB 2.0 app that lets users find, track and join conversations found on the internet.
It starts out as a search engine that you subscribe to. Then it morphed into a "conversation-search engine with tools that help to create communities around popular topics.
It may be regarded as comparable to Technorati...but with some different features.

"D" says..."all of the above...plus check it out"

here's a screen and a link