I like the concept! Because you need friends who also have installed FrameParty, I think that an "invite friends" function right in the app would help. I was hoping to be able to send an app download link to a couple of Facebook friends. For now, I have to leave the app to tell them to search for it in the app store, download it, then tell me what their username is. If you could streamline this process somehow, I think that you'd see more signups.
Thanks for the feedback! That's definitely on the roadmap (probably the next thing I'll work on). Facebook for sure, maybe Twitter as well?