Radio4000 - Radio4000 lets you discover user curated radios from around the world, manage your online music...
Spotify - Map shows when two people play same song at same time
Bandcamp - Discover amazing music and directly support the artists who make it.
SoundCloud - Enjoy music & follow favourite artists
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
Audiomack - The free SoundCloud alternative