The idea is really nice! Maybe i would work a bit on the design, also maybe try not to focus on the same genres. This is something that is bugging me a lot with all these website like your, consle.fm etc... i really like theme but they focus on music kinds i am not interested in. I mean on your top bar there are at least 6 musics for "disco" and 1 pop/rock... this demotivates me because maybe i would love to see a "classical music" and "metal" etc... i think that if you expand your music horizonts you might expand your target audience and really stand out of the crawd of similar websites.