The malaria parasite has been killing children and sapping the strength of whole populations for tens of thousands of years. It is impossible to calculate the harm malaria has done to the world.

You can go overboard in how quickly you might expect new technologies to transform people's lives. But I very much believe the way software is used, the way information gets distributed, will be dramatically different within 10 years. There is fire to go with all this smoke.

I want to admit that I am an optimist. Any tough problem, I think it can be solved.

I was lucky to be in the right place at the right time. But many others were also in the same place. The difference was that I took action.

Microsoft does not dominate the software industry by any stretch of the imagination. We have lots of very able competitors who keep us constantly vigilant, and sometimes they beat us to the punch. Microsoft's success to date is based solely on the fact that people like Microsoft software.

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.

People in business understand paying money to be more efficient. You can bootstrap markets where the devices are too expensive at first because these are so valuable to some people.