Heartbeat - Listen to music with your friends together, on Spotify
Spotify - Map shows when two people play same song at same time
Festify - Festify is a free Spotify-powered app that lets your guests choose which music should be played...
Last.fm - The world's largest online music service. Listen online, find out more about your favourite artists, and get music recommendations, only at Last.fm
BeatSense - Discover great music hand-picked by real people, in a single click. FREE and in real-time!
SoundCloud - Enjoy music & follow favourite artists