The first thing I thought of was something I saw at a weekend hack event: in a disaster or when no network can be found, it looks for nearby phones over blutooth and propogates messages until the original message eventually finds a phone to send out a communication over data or wifi.
Yeah I love the idea of this kind of robust mesh. I think it'll happen eventually. Alternatively it could propagate until it reaches whoever it's going to on the limited network (your friend in a different neighborhood) and then send out a kill order for the other propagating packets.
The kill order sounds like it could waste as much bandwidth as the duplicated message copies, and be exploitable to suppress messages unless it requires a signature from the message's recipient.
I like that idea, but I'd guess Bluetooth range would limit it. I wonder if you could do something with special packets and wireless cards in promiscuous mode?
