Geographically distributed smart chatrooms.
GeoParty creates chatrooms based on your geographic location. Users near each other will be placed in the same chatroom, and can chat with each other or send files.
GeoParty also allows scripted response for common questions asked by people in the chatroom. For example, if the chatroom users would like to meet up in person, it is useful to know what the weather is like in a particular location. GeoParty connects to weather sites and provide this handy information as part of the chat room. This can be extended for other type of usage.
No setup required, just a browser. Mobile or desktop works just as well.