SoundGrail - SoundGrail Music App designed for pianists, guitarists, and DJs.
AMPLI.FI - Live online music community. Twitch for tunes.
Figure - Propellerhead creates world-class software products and services that inspire music makers and provide the foundation for a worldwide creative musical community.
Krue - Twitch for music: live streams from amazing musicians
keezy - A colorful soundboard. Play with music.
Soundscape - Sync your music with the open source community