I don't know much about the target market, but I would try and get people passionate about promoting their favorite artists/songs to this site. You could find

I don't know much about the target market, but I would try and get people passionate about promoting their favorite artists/songs to this site. You could find forums for specific music categories (electronic, hip-hop, rap etc) and try driving traffic from there to leapfm by posting links to top songs from the category. You could also try and get them to upvote music of the specific category. You can target Facebook fan pages of artists that have songs posted on leapfm. Try and get the fans to Share the link and upvote the artist on the site.