I believe that in this context the group of people who are advocating for things like civilian run mesh networks are not advocating that we *replace* the Internet as we know it today with these networks as so man Slashdotters seem to be assuming. They are not talking about having these systems in place for watching movies on Netflix, or for telling all your friends on facebook that you just farted.
Rather, the point is so that in a state of emergency (i.e., the government has completely lost it's marbles and decided to declare martial law and thereby shutdown all civilian communications) these networks can be used to continue to take advantage of the kind of instant mass communications our society has come to rely on. The point is so that you can still contact your family back on the other coast, or tell your friends you're hosting a meeting to talk about how to handle the national guard unit stationed around your neighborhood for your own "safety", ...etc.
I think really, they just want to be able to send e-mail, and post in online forums.
Personally, I think it's too late. If, for example, the US federal government decides to "go Egypt on our asses", they're going to do it in the next few years, well before we have time to setup any sophisticated civilian run mesh networking. Our only hope is to make sure that such a thing never happens by pressuring our politicians hard, and getting our friends to do the same...