Spotify - Map shows when two people play same song at same time
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
Pandora - Pandora Radio is a free (ad-supported) internet radio founded in 2000.
SoundCloud - Enjoy music & follow favourite artists
Maloja - Simple self-hosted music scrobble database to create personal listening statistics.
TuneIn Radio - With TuneIn Radio Mobile, your mobile device becomes the radio.