Spotify - Map shows when two people play same song at same time
Prodigy - Radically efficient machine teaching
SoundCloud - Enjoy music & follow favourite artists
Genius - Genius is the world’s biggest collection of song lyrics and musical knowledge.
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
Shazam - Shazam is a mobile app that recognizes music and TV around you.