Wacht.tv - Reddit meets MTV, discover music videos!
FIEND.fm - "Hot or Not" for music discovery: 2 hrs of tracks in 2 mins
DiscoverWeekly.dev - The playlists made by devs, every Wednesday
Pacemaker - Create and share mixtapes with friends
SameTunes - Music social network to compare, share, and discover music.
Boil the Frog - Create a seamless playlist between any two artists