MusicTwin Finder - Find your MusicTwin by your Spotify playlists in 5 seconds.
humit - A social networking app for music sharing and discovery.
JamBuddy - Find and collaborate with musicians around you thru Spotify
Cymbal - Music discovery powered by friends
Liyo - Stream your favorite music live with friends 🎶
Better Notes - Simple notes app that ties notes together with #hashtags