AMPLI.FI - Live online music community. Twitch for tunes.
Keezy Drummer - Make a beat in seconds
Bandlab - Capture, nurture, and collaborate on song ideas in the cloud
Radium - Radium is a music editor with a new type of interface.
Blattarco - Creative self-developement for musicians of all level.
BlokDust - Join blocks together to build sounds with this web-based music making app.