The idea is good, but the way you communicate it is inefficient, if you fix that it can easily become successful. Replace the App by a anonymous web-service that uses firebase or websockets to communicate to users near you. People can sign-up by e-mail + gravatar, but sending private messages should be possible anonymously. If that doesn't work good enough, integrate it with Path/Foursquare.
This is fantastic advice. I appreciate it. We were looking into setting up some kind of proximity location and communicating that way but, in 24 hours, settled on what we knew. Long term, though, this is a good idea. Thanks!
Would you please keep me updated and tell me, if you're successful with the startup or not? How can I reach you?