Nice project. I'd suggest adding a like/ignore option to anonymous users.

Also, don't miss this comment https://news.ycombinator.com/item?id=12804222

There is a small cross in the corner of messages. The underlying menu allows for both reporting/blocking of a particular user.

I've had an idea like this in my head for awhile now. One use case, you're at home and something just happened, large car accident, loud noise, etc and you want to be able to chat with the people around you while sitting on your couch.

When stuff happens around me when I'm sitting at home I find twitter to be too slow to update and it has a lack of information anyways.

But then you're just dealing with the same network effects that twitter is having trouble with.

Ham radio works for me. The power went out a few weeks ago. In the time it took me to walk across the room and turn on the radio they were already talking about it. I didn't bother to transmit, I didn't need to ask. In the next few minutes I heard reports from across the area, who had power, who didn't. It was way faster than waiting for news on facebook. I had a similar experience when there was a large amount of smoke blowing through. Was it something close or from a neighboring state? Ham radio is pretty simple and you can get started for $50 (radio and test). What does it take? Check out http://hamstudy.org (no affiliation, just a happy user).

I don't have an iPhone to try it out, so a few questions.

1. Do you need to "log in" to use it? Or can it be used without an account?

2. Can you have hidden/secret conversations? That is, the conversation isn't easily observable by everyone within 1km?

There is no sign-up required what so ever.

If one wishes to continue a conversation one-on-one I believe other applications are better suited for that. I therefore build only one private function:

The exchange of contact details if both parties agree. If one wishes to participate in an exchange of details. It is also for this function only required to fill in some form of details. The idea being you can than continue your conversation in private elsewhere.

Does it really work on a train as in the example? Having the GPS work reliably on high speed trains seems like a challenge, more so if you need to rely on cell data connection and everyone having their GPS synchronized properly.

I think you are "over quota"