THIS is something I've been anticipating for a long time. TurnTable(dot)fm (RIP) inspired the concept in my mind. Happy to have discovered this platform...though I have not tried it yet. I'm simply enthusiastic about the concept. Related product is NetflixParty. However, my specific interest is in synchronized music playback from SoundCloud, MixCloud, Spotify, etc.
I can only hope that it evolves quickly and is or becomes mobile compatible. Very excited to see where this goes. Hopefully the founders/developers will join in this discussion.
