There's a glut of online music streaming services battling for your social timeline. Spotify, Grooveshark, Last.fm and Rdio all exist to annoy your Facebook and Twitter friends with the latest tune you listened to and what you think everyone else needs to hear. It's like cranking tunes in your bedroom as a teenager, except the echo-chamber is the entire online world. What's better than indiscriminately forcing your musical taste on your drinking buddies, high school aged cousins and accountant uncle?