It is now a while that I am seeing signs of evolution/revolution at the network edges. Already at the turn of the century it was becoming clear that radio communications would be possible among devices in such a way to create real networked devices. With iOS 4.3 we started to have tethering on iPhone (and a few Telecom Operators rushed to find ways of blocking it so that they could sell one SIM card per each device you wanted to connect with the Internet, or offering "premium" contracts to let you do that...) and then we saw AirPlay to create home networks where our iPad could talk to the AppleTv and from there to the television...
Now I started to use FireChat, and did it for a few days before writing this post. With FireChat (you can download it from the Apple Store and try it right away, it is free) you can exchange messages among iPhones in the vicinity with no need for an Operator network, not even a WiFi network connected to Internet.
FireChat exploits multipeer connectivity made available by iOS7 to let iPhones chat one another via Bluetooth or WiFi they generate.
I can easily imagine a school class with students using FireChat ...
True, messaging has become so cheap (the actual perceived cost approaches 0!) that there may be little incentive to use FireChat but on the other hand I see this as a starting point for real networks at the edges, actually networks that are separated from the edges. They exist on their own.
I can see these kinds o networks forming in a mall, in an office, at school, and even at home, creating a way for devices to acknowledge each other and create ambient awareness.
FireChat has been developed by Open Garden, that very aptly is using as a slogan "You are the Internet". So far the multi peer connectivity provided by iOS7 support communications among devices within range of one another (you can communicate with your iPhone to another one or to several iPhone and iPad as long as they are within reach of one another, that is within a 30 m circle) but you cannot hop from one iPhone to the next and then hop further leveraging on the reach of the second, third fourth and so on to travel whatever distance provided that each hop is within radio reach. Open Garden plans to get rid of this limitation and support multi hop communications based on multi peer connectivity. This means that cell phones in a city would actually create a network that covers the all city!
It may not be good for voice communication (it is not, because of the delay introduced by each hop...) but it can be pretty good for a variety of services, including multiplayer gaming. And for sure it can prove "vital" in those cases where the network is lost because of some disaster, like earthquake or flooding.
It as also been pointed out that messages exchanged across this sort of opportunistic networks are never stored in any server and therefore more protected from the bad guys (and the good ones too...).