At some point, that risk-taking private capital can take over, and have patents and trade secrets and things that let them lead the way, which happened with the steam engine and some other things, although with energy, the time of adoption is a lot longer than it is with, say, IT products or even medical advances, like drugs and vaccines.

Unfortunately, the highly curious student is a small percentage of the kids.

Until recently, over 98 percent of teachers just got one word of feedback: Satisfactory. If all my bridge coach ever told me was that I was 'satisfactory,' I would have no hope of ever getting better.

I think there certainly was a milestone in the '90s with regards to the Internet achieving critical mass. There were several magical factors that came together: the creation of HTML by Tim Berners-Lee, the drop in the price of communications, and all the PCs out there that you could put this software into.

Well-spent aid money is saving lives for a few thousand dollars per life saved.

With polio, we've gone several years with no polio in all of Africa, but now with this we're having to go and mop up in that whole region, so it's a bit of a setback for polio. So in parallel we have to go back and get rid of those cases.

What I do best is share my enthusiasm.