Might be a nice idea to buy communities like github, photo.net and import user identities from there. Of course the privacy and the UX of such a move will dicta

Might be a nice idea to buy communities like github, photo.net and import user identities from there. Of course the privacy and the UX of such a move will dictate whether users go "wow this is great" or "oh my god now the whole internet knows about my tinfoil hat". In the meanwhile they could try to integrate identities from services that google already owns - youtube, picasa, google reader etc.