India just went 3 years with no cases [of polio]. Pakistan is our toughest location right now because some parts of the Taliban have not allowed vaccinators to come in and have even attacked vaccinators. We are hopeful this will get resolved since no one wants their kid to be paralyzed. I spend a lot of time making sure the polio campaign is doing the best it can. We have great computer models that help guide our activities.

It's an experiment, and it's probably good to have a couple states try it out to see before you make that national policy.

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.

Should surveillance be usable for petty crimes like jaywalking or minor drug possession? Or is there a higher threshold for certain information? Those aren't easy questions.

I think it's fair to say that personal computers have become the most empowering tool we've ever created. They're tools of communication, they're tools of creativity, and they can be shaped by their user.

The challenge here is to design a system where market incentives, including profits and recognition, drive those principles to do more for the poor. I like to call this idea creative capitalism, an approach where governments, businesses, and nonprofits work together to stretch the reach of market forces so that more people can make a profit, or gain recognition, doing work that eases the world's inequities.

Giving money effectively is almost as hard as earning it in the first place.