http://blog.twitch.tv/2015/01/twitch-brings-music-to-broadcasters/
Music Category Beta
We are also announcing an experiment with music content creators: ourbeta Music category. The Music category—listed among the game titles you can designate for a broadcast—is for musicians to use for creating, performing, and presenting original music.
Artists such asDeadmau5,Steve Aoki,Porter Robinson,Fred Durstof Limp Bizkit, and many others have already turned to Twitch to launch channels to play games. With the beta Music category, they are now able to make music a part of their Twitch presence.
You will continue to see performances (e.g., concerts, music festivals) by professional artists. We will also showcase “radio shows” created by approved labels.
To this end, we’ve kicked this off by working with Monstercat’s new24-hour Twitch music channelcalled Monstercat FM. Monstercat has been experimenting with Twitch broadcasters to use the Monstercat channel as a new radio-style music player during their broadcasts.
We encourage all music creators to share your content live on Twitch and to engage with your Twitch viewing audiences during broadcasts just like gamers do via chat participation.