From my bedroom I can pick up (though not log on to) the WiFi network of seven neighbors. Would it be possible to set up a neighborhood-wide WiFi network using everyone's WiFi routers? We couldn't talk to the outside world but could we send messages and information between houses in this manner? That in it's own way would be a good safety net.

I can envision a local HAM posting news updates, a nurse or doctor being on call to respond to a medical emergency, someone passing files to people on treating water, etc...

-Blast