I listen to jazz on Earbits for a bit 4-5 times per week. Really enjoyed it, but it seemed there were limits to what I could discover but was fine cycling through a lot of the same stuff.
None of the social features or other genres really enticed me so I was doubtful the model would scale. For example, I listen to a lot of electronic music and there's no reason why I would go to Earbits over SoundCloud, YouTube, TheFuture.fm, or other sites. Unfortunately since it was so listener-centric without enticing social or discovery features, I didn't see how it could be a differentiator (other than some quality music from artists you've never heard of).
I'm sad to see it go though. Same with ex.fm.