Mesh networks (like those the protesters are using with their phones via blutooth or wifi) are quite interesting, It's a shame that the FCC won't allow them.
There's this great product called gottena coming out later this year that connects to your phone via blutooth and uses encrypted VHF packet data to send and recieve texts. It has a range of 1 to 50 miles depending on line of sight and other environmental factors but can work in a mesh mode where you can message someone or of range if there is someone in between you that you can both reach. Unfortunately though, they can't use this feature in the US because of regulations against mesh networks. Not using any public networks and using strong encryption it's actually a pretty secure way of chatting (unless your using the public open chat mode, sort of like a CB radio chat room).
The weakness of course is the fact it's operating on your phone and whether your using an iPhone or an android handset most governments (or anyone willing to spend a couple bucks on commercial spyware) have the capability to snoop in your phone even if they can't snoop on the signal. It's a pretty open secret that what's going on in Hong Kong with the phone snooping is par for the course all over the world in similar situations.
I'm sure gotenna will be quickly picked up by drug dealers and the like but it could be pretty helpful in a situation like the HK protests.
Couple interesting articles:
http://apple.slashdot.org/story/14/10/01/174212/ios-trojan-targets-hong-kong-protestors
http://it.slashdot.org/story/14/10/01/186228/obama-administration-argues-for-backdoors-in-personal-electronics
