Sometimes, I think my most important job as a CEO is to listen for bad news. If you don't act on it, your people will eventually stop bringing bad news to your attention and that is the beginning of the end.

I'm going to save my public voice largely for the issues where I have some depth.

[Smart] is an elusive concept. There's a certain sharpness, an ability to absorb new facts. To ask an insightful question. To relate to domains that may not seem connected at first. A certain creativity that allows people to be effective.

My experience of malaria was just taking anti-malarials, which give you strange dreams, because I don't want to get malaria.

Imagine, just for the sake of discussion, that you had a few hours a week and a few dollars a month to donate to a cause - and you wanted to spend that time and money where it would have the greatest impact in saving and improving lives. Where would you spend it?

I've been studying how quickly we can get energy out to the poor countries - a lot of which are in Africa - and how little progress we've made there. There's no more electricity today in sub-Saharan Africa per person than there was 20 years ago.

I'm certainly well taken care of in terms of food and clothes ... Money has no utility to me beyond a certain point. Its utility is entirely in building an organization and getting the resources out to the poorest in the world.