Last.fm keeps track of all the music you play but they also keep track of the music that people don't want the world to know they listen to: the Most Unwanted Scrobbles. The Beatles, Radiohead, Britney, and Avril top the uncharts. The Britney and Avril I can understand. The Beatles and Radiohead...perhaps the perception of overratedness leads people to keep those tastes private? (thx, graham)
Update: Ohhh, ok. Radiohead and The Beatles are so high on the list because 1) so many people have those two bands in their playlists that they get deleted so much out of sheer numbers, and 2) those two bands are no good for recommendation engines -- you like pop music? I recommend The Beatles -- so people exclude them. (thx all)