It was really phenomenal [Warren Buffett donation]. It grew out of the friendship that we had and the fact that his plan to have his wife run the foundation and give things away changed when she tragically died.

If you're using first-class land for biofuels, then you're competing with the growing of food. And so you're actually spiking food prices by moving energy production into agriculture.

There's only one trick in software, and that is using a piece of software that's already been written.

The general idea of the rich helping the poor, I think, is important. That your sense of justice says, why should rich kids - who barely get these diseases and almost never die of them - why should they get the vaccines, when poor kids, who actually do die from these diseases, don't get those things? It's an unbelievable inequity that there isn't that access.

The competition to hire the best will increase in the years ahead. Companies that give extra flexibility to their employees will have the edge in this area.

The only thing I understand deeply, because in my teens I was thinking about it, and every year of my life, is software. So I'll never be hands-on on anything except software.

We make the future sustainable when we invest in the poor, not when we insist on their suffering.