The authors give us a cluster of answers, overlapping and bumping up around the edges. Radical freecyclers; urban-squatter tribes; nomadic communitarians; and, most interestingly, virtual citoyens crosshatching their invisible cities over the existing ones.
All the stories are thoughtful and good. The weakest is Scalzi's, which doesn't manage to elevate itself past the shaggy-dog level, but it's well-told anyhow.