Just wanted to point you to thesixtyone if you don't already use it. It's really one of the few next-gen websites that I think really does it right. Thesixtyone calls itself a "music adventure" — you earn XP for listening to music as well as reaching various milestones.
You can support songs you like by bumping them. Bumps cost XP, but the more popular the song gets, the more XP you earn for having supported it. Sign up for free as a listener or an artist, and start leveling.