You have to be willing to see that sometimes the governments of these poor countries don't come through. You have to think about that as a constraint. How do you help them be better? How do you come up with things that actually work, even in those tough situations.

I keep bumping into that silly quotation attributed to me that says 640K of memory is enough. There's never a citation; the quotation just floats like a rumor, repeated again and again.

We're still missing about a dozen vaccines that will make a huge difference. For adults, we've got HIV and TB are still huge; for kids malaria is still killing a half million kids a year out of that 6 million. We probably need some vaccines, but we need a little more data to make sure we're getting the vaccines that will save the most lives.

Philanthropy is fun and fulfilling.

When Paul Allen and I started Microsoft over 30 years ago, we had big dreams about software. We had dreams about the impact it could have.

Money has no utility to me beyond a certain point.

This social-networking thing takes you to crazy places.