I saw Musicmatch float by on Facebook and Liked it. I reminisced about one of my favorite features, Musicmatch AutoDJ.
It was fun seeing it come to life with the team. Create all sorts of playlists from your On Demand service and MP3 library. In 2004 it was the first auto-playlist creator based on artist seeds, relationship diversity, popularity, release date, and size (#of tracks, time or bytes) combing tracks from your MP3 library and On Demand (Spotify like) subscription service. Old drawings and remnants of the spec are here: http://www.google.com/patents/US20060265421. Best dog food I ever ate.