Suppose the wifi radio on a phone or computer is powerful enough to transmit/receive signals up to 100 feet away with a direct line of sight, and 50 feet away t

Suppose the wifi radio on a phone or computer is powerful enough to transmit/receive signals up to 100 feet away with a direct line of sight, and 50 feet away through walls. In a dense urban environment like Beijing or Shanghai, I bet a topologically connected mesh network across everyone's phones and computers could become quite large. It would be completely un-censorable. The network graph wouldn't even always have to be topologically connected; devices jumping between disconnected subgraphs of the network could cache content while attached to one subgraph and dump the cache when in range of another subgraph. This would be impractical for real-time messaging or large media content, but would likely be sufficient for a Twitter-like microblog service. The main challenge with setting such a system up would be decentralized distribution of the app that would run it. It is impossible to sideload apps on iOS, and tricky enough on other platforms via fully decentralized means (e.g. P2P wifi or Bluetooth connection) that I doubt you could reach a level of saturation for a mesh network to be practical. At best, it could probably function like a relay — the app would detect when you're close to someone else who also has the app and automatically exchange cached content between devices that you each don't yet have.