Just wanted to chime in and say I get you, man. "Chat with people within 1 mile" is just a better thing than "Chat with people within a radius adjusted based on how many users are online nearby."
Yep, that's fair enough. And you certainly don't have to make an app that's useful for everyone everywhere. Still, getting it to catch on will be hard enough even if people can find others to chat with, it makes sense to do what you can to help with that. How about keeping the tagline the same, and keeping it at 1 mile as long as there's someone there to chat with. But if not, you could prompt the user: There's no one else online within a mile. Want to look a bit further away? Or something along those lines.
