At Grooveshark, we have a feature that does this and it works amazingly well. If you click on the people icon at the upper left hand corner of the screen you'l

At Grooveshark, we have a feature that does this and it works amazingly well. If you click on the people icon at the upper left hand corner of the screen you'll see a feed of what your friends are currently listening to on Grooveshark. The feature has become so useful, that I often discover new music to listen to through it much more so than algorithmic recommendations. Social recommendations are indeed the best way to discover new music. In fact, one interesting example of this is when one of our co-workers began recommending everyone listen to Mumford and Sons about 10 months ago. Within a month, everyone feeds were filled with Mumford and Sons playlists. I remember looking at my feed and thinking "Who the hell are Mumford And Sons". Turn's out they're awesome and blew up.