22tracks - DJ curated Spotify playlists on iOS
Songlink - Share music with anyone.
BandNext - Discover bands that sound similar to artists you already love with BandNext. A single click saves your results to a Youtube playlist.
humit - A social networking app for music sharing and discovery.
Spotify - Map shows when two people play same song at same time
aux.app - A free web-based music platform to play music from other popular online streaming services.