One thing I've always loved about the culture at Microsoft is there is nobody who is tougher on us, in terms of what we need to learn and do better, than the people in the company itself. You can walk down these halls, and they'll tell you, 'We need to do usability better, push this or that frontier.'

What are the top 20 universities in the world that do good materials research that might create carbon fibers to do jet stream kites or new magnets that will allow [energy] generation to be done up there and you just bring the electricity down. You either have to bring down rotational energy, which is hard, or you have to have the generator up there and bring down the electricity. Well, putting the generator up there is hard to do because it's too heavy.

Climate change is a terrible problem, and it absolutely needs to be solved. It deserves to be a huge priority.

Long-term vision and product strategy.

Who can afford to do professional work for nothing? What hobbyist can put three man-years into programming, finding all bugs, documenting his product, and distributing it for free?

The first rule of any technology used in a business is that automation applied to an efficient operation will magnify the efficiency. The second is that automation applied to an inefficient operation will magnify the inefficiency.

The first five years have so much to do with how the next 80 turn out.