Turntable.fm - Turntable.fm is a social media website developed by Billy Chasen and Seth Goldstein that allows the audience to stream their own music.
CyTube - Free, open source synchtube
Bandlab - Capture, nurture, and collaborate on song ideas in the cloud
Metastream - Watch streaming media with friends
Audiu - Audiu is one of the largest platforms for the online music community, allowing users to collaborate, organize and publish their musical projects.
Watch2Gether - Watch2Gether is an app that allows multiple people to watch the same content simultaneously and interact with each other while watching.