Urban retrofitting: creating different sorts of spaces and uses out of places that are already there.

The planet's biggest problems have to do with sustainability, environmental decline, global poverty, disease, conflict and so forth. Really, they're all interconnected - it's one big problem, which is that the way we're doing things can't go on.

The denser places get, the lower the amount of energy people use to get around it.

There's no law of physics that says we have to be an unsustainable society - in fact, quite the opposite. The planet's ready to work with us if we're ready to think differently, but we do have to make that jump and start to do things in new ways.

In almost all city governments in America, the small group of people who don't want change are able to block change.

We get so little news about the developing world that we often forget that there are literally millions of people out there struggling to change things to be fairer, freer, more democratic, less corrupt.

For most people, using the Internet broadens their sense of who 'we' is and actually ends up leaving us in a place of greater compassion and understanding. It leaves us more connected to a larger group of people and more at one with a lot more people in our community.