Gonic - music streaming server / free-software subsonic server API implementation - sentriz/gonic
Spotify - Map shows when two people play same song at same time
Swing Music - Beautiful and fast music streaming server.
SoundCloud - Enjoy music & follow favourite artists
MusicDB - MusicDB is a music manager, server and player that focus on music.
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