We remain somewhat sceptical about the mainstream appeal of ‘DJ live to your friends’ apps, given the lukewarm longterm popularity of sites like Turntable.fm. Even so, new player SpotCast is interesting for a couple of reasons. Launched initially as a Mac application, it lets people DJ through Spotify while friends listen in real-time, also through Spotify. But it’s also the first music app we’ve seen that uses App.net – the new Twitter-alternative service launched by former Imeem boss Dalton Caldwell – as an option to log in. That said, it also uses Twitter.