I took a look at FireChat, but bluetooth is a bit too 'nearby' for me. Very cool that it's off the grid, but only useful if you're basically right next to them anyways. I wanted something like: talk to everyone nearby in a football/hockey/tri-d chess stadium, but bluetooth falls a bit short. What would be really cool is if you could set up a relay system through other devices. I've made (i.e. works, but not polished…
I'm also very disappointed in the Wi-Fi Alliance for not creating a better long-distance Wi-Fi. That's its future right there - disrupting cellular, and getting more people to prefer Wi-Fi over cellular. But that's only going to happen if we can easily create "mesh networks" across the country.