TasteDive - TasteDive recommends similar music (musicians, bands), movies, TV shows, books, authors and games, based on what you like.

BandNext - Discover bands that sound similar to artists you already love with BandNext. A single click saves your results to a Youtube playlist.

Gnoosic - Even if you don't know what you are looking for - gnod will find it.

Spotify - Map shows when two people play same song at same time

LivePlasma - Discovery engine map for books, music, and movies

stats.fm - With the click of a button you'll be logged with your Spotify account and you'll instantly gain access to a valhalla of cool stats and insights.