Bandcamp - Discover amazing music and directly support the artists who make it.
Openwhyd - Collect and Share the tracks you love.
SoundCloud - Enjoy music & follow favourite artists
SoundClick - SoundClick is a music-based social community.
Pandora - Pandora Radio is a free (ad-supported) internet radio founded in 2000.
Zoff - Collaborate on a live music and video playlist with your friends.