In fact, that's where my vision of the coming digital opportunity is somewhat different from other people's. I divide it into three parts. One is the office. That's the one I'm most excited about and is the most concrete.

Effective philanthropy requires a lot of time and creativity - the same kind of focus and skills that building a business requires.

Whenever you have multiple devices including multiple PCs that you want to share information with, it's always been a bit complicated.

If you really could take the CO2, when you burn hydrocarbons - coal, for example - if you could really capture the carbon and sequester it - they call it CCS - if the extra capital cost, energy cost, and storage costs over time didn't make it super expensive, then that's another path that you could go down.

Make it just like a Mac.

We're very enthused about the idea that in the third trimester we actually give the mother a vaccine and her antibodies, the protective things that the immune system makes, actually pass through to the baby, both when the baby is born, and through the mother's milk. Because the baby's immune system is actually not very strong for that first few months, using the mother's immune system to do this - it's a very exciting idea and something that we're investing heavily in.

I was announcing to the public, in 2006, that I'd be leaving Microsoft in a couple of years and focusing full-time on the foundation. That was the time at which we went back to New York and Warren [Buffett] announced these gifts to a number of foundations, with a very high percentage of it going to us and basically doubling our capacity.