Spotify - Map shows when two people play same song at same time
Listenbox - Podcasts from audio & video on the web
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
Audioship - Upload audio to YouTube or Facebook
SoundCloud - Enjoy music & follow favourite artists
TunesToTube - What does TunesToTube do?