If you want to build a great company, get the hell out of Silicon Valley.

Every three years, we have to go to the governments and say, okay, you know you're saving millions of lives and even though your budgets are tight, helping Africa avoid this disaster really is a priority.

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?

The United States has a huge budget deficit so taxes are going to have to go up and I certainly agree they should go up more on the rich than everyone else. That - that's just justice.

[Africa] is the one continent where you still have a lot more young people than old people. So making sure they're healthy, good nutrition, good education. That'll be important for the world.

in china when you're one in a million, there are 1300 people just like you

Polio's pretty special because once you get an eradication, you no longer have to spend money on it; it's just there as a gift for the rest of time.