If you log in, and no one is around, the app gets closed pretty quickly. I have checked back multiple times, and always seem to miss everyone chatting. I would love to know if someone close by is online or chatting, so that I don't have to sit there hoping someone sees my tepid 'Hello?'.
I don't know if push notifications are the correct answer, but letting me know that there was activity that I missed, after my last post, would be a good start. Letting me know if other people are active in my region would be nice, but it's mostly that I don't want to have a conversation with myself.
I would love to know if other people are chatting, because I want to join in.
In any case, thanks for the app, have you got a public issue tracker, or anything similar?