It is hard to sell Congress and the American people on foreign aid. Is it harder to do that than it is to sell billionaires on the idea that they should give all their money away.

Looking at these issues as a businessman, I believe that investing in the world's poorest people is the smartest way that our government spends money.

Certainly, the Windows share of servers is strong.

The bulk of the universities are about teaching kids.

The answer is simple, and harsh. The market did not reward saving the lives of these children, and governments did not subsidize it. So the children died because their mothers and their fathers had no power in the market and no voice in the system.

Software substitution, whether it's for drivers or waiters or nurses ... it's progressing. ... Technology over time will reduce demand for jobs, particularly at the lower end of skill set. ... 20 years from now, labor demand for lots of skill sets will be substantially lower. I don’t think people have that in their mental model.

Your most unhappy customers are your greatest source of learning.