I’ve read about them, but I don’t know enough about them to implement one without lots of headaches and research. They have been on my mind more and more though with the happenings in Egypt, Libya, and now on home turf in San Francisco.
We all carry around these devices which can both broadcast and receive on multiple frequencies, the two of primary interest being Bluetooth and 802.11 Wi-Fi. Bump has proven that we can use Bluetooth to transfer point to point, sure they do some authentication on their servers and require users to accept the transaction but a proof of concept is already there. Combined with one of the several mesh routing techniques and perhaps something like onion routing where only the destination node can read the message… sounds like a feasible mesh network.
Without the onion routing you have the same problem as CBs one can sniff all the traffic on the network and learn what is going on. Protesters use police scanners to do the same thing that police could do with CBs to monitor traffic. The alternative is to use something like public/private key, which only works if you have set it up ahead of time, unlikely in the ideal use cases like protests.
Another potential problem is the needing a rooted phone for broadcasting a wireless node, limiting non-rooted phones to single point to point communication, or connecting as an end node to a Wi-Fi network that someone else is broadcasting, or using Bluetooth which I don’t know the limitations on whether they can multicast or would have to connect to each other phone individually.
Yet another potential problem is battery life. When I tether it drains my battery quickly. I have not confirmed that this is purely the broadcasting and not the combination of broadcasting as well as connecting on 3g. Bluetooth appears to be more battery efficient and newer versions of the protocol/hardware is getting better/more efficient.
A note to those who will read this and rip it apart, I’ve not done any research for the piece directly, just reading about things when they peaked my interest months ago. If you have any corrections please add them (preferably with source) to the comments and I’ll gladly update the post.