I was an mp3.com artist back in the day. It was truly the independent music revolution that people cry out for - basically it was good enough that normal listeners came there to find music - no alternative has successfully provided that marketplace since. It was killed by a $200 million settlement against them for allowing streaming of copyright content that had nothing to do with the independent artists.

Garageband.com ended up taking over a large portion of their database and has fairly similar capabilities. I've found a number of artists I like from that site.