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.

Cities offer us powerful leverage on our most stubborn, wasteful practices. Long commutes in our cars, big power bills from our energy-hogging buildings, shopping trips to buy stuff that'll spend a few short months in our homes and long centuries in our landfills.

For carbon-neutral cities, there are things worth talking about in how our consumption patterns can change - sharing goods, etc. - but those are a fraction of the impacts of transportation and building energy use. If we need to choose priority actions, the most important things are to densify, provide transit, and green the buildings.

There are a lot of different ways of building a prosperous society, and some of them use much less energy than others. And it is possible and more practical to talk about rebuilding systems to use much less energy than it is to think about trying to meet greater demands of energy through clean energy alone.

I agree completely with my son James when he says 'Internet is like electricity. The latter lights up everything, while the former lights up knowledge'.

Advances in technology and the Internet have dramatically changed the way we communicate, live, and work.

The upside of social media is you can craft how you want people to see you in some way.

One of the ways that Microsoft beat Apple way back in the day was that they were a lot more open; today, in the world I come from, the free software and open-source world, Microsoft is not generally viewed as open; they're viewed as proprietary.