The trick generally is to break programs into pieces and have those pieces be individually testable and so then when you move on to the other pieces you treat it as a black box knowing that it either works or doesn't work.

I want to admit that I am an optimist. Any tough problem, I think it can be solved.

To get a big company moving fast, especially on a many-headed opportunity like the Internet, you have to have hundreds of people participating and coming up with ideas.

I don't think there is any philosophy that suggests having polio is a good thing.

I really do think cancer will largely be a solved problem. I think most of the infectious diseases like malaria - our foundation is very involved - once we're finishing polio eradication, then starting up this malaria eradication, and getting that done as fast as we can.

Part of the magic of economic growth is how you educate people, and the leading economies have to stay in front of that. From an economic point of view, it affects competitiveness and creates jobs. Or from a social justice point of view, you can take someone in the bottom tier of income and let him compete to be a doctor or lawyer. The education system is the only reason the dream of equal opportunity has a chance of being delivered - and we're not running a good education system.

There's always a tricky issue when you get into stolen material or pornography. The laws for online publishing the same as for print-based publishing, where if you're hosting certain types of things and somebody notifies you about that.