The new Couchsurfing? Judging by their recent troubles, sounds like the time is right for something new & app-based in the same space. I think it's smart to grow the community one city at a time like Party with a Local are doing. Berlin seems a smart and obvious choice for the next city - it has an amazing party scene, if you know a local or where to look!

Good idea to focus on one platform first. But isn't it better to choose Android first for this target audience? Also, is Berlin the right city to do next?