Concept:

A combination of the play data aggregator and MP3 content resolver.  It looks at your Last.fm, Imeem, Rhapsody and Hype Machine recently played tracks (as well as bookmarked songs from Pandora). It then searches for MP3s for each of them, then returns and/all it can find in a playlist/podcast.

          Screencast:  How to passively program a "twitter radio" station

Yahoo Pipes:

• For Twitter (shortened URLs & hashtags):  http://tr.im/hqNt
• For lifestreaming services, podcasts, blogs and everthing else:  http://tr.im/hqEU