Spotify - Map shows when two people play same song at same time
Radio4000 - Radio4000 lets you discover user curated radios from around the world, manage your online music...
SoundCloud - Enjoy music & follow favourite artists
Bandcamp - Discover amazing music and directly support the artists who make it.
Ampache - Web ( HTTP centralized ) based audio/video streaming application
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