In Gillette's case, they keep surfing along new technology which is fairly simple by the standards of microchips. But it's hard for competitors to do. So they've been able to stay constantly near the edge of improvements in shaving.

You've got to have models in your head and you've got to array you experience - both vicarious and direct - onto this latticework of mental models.

The tradition of always looking for the answer in the most fundamental way available - that is a great tradition, and it saves a lot of time in this world.

I'd say 3/4 of advertising works on pure Pavlov. Think how association, pure association, works. Take Coca-Cola company (we're the biggest share-holder). They want to be associated with every wonderful image: heroics in the Olympics, wonderful music, you name it. They don't want to be associated with presidents' funerals and so-forth.

Mutual funds charge 2% per year and then brokers switch people between funds, costing another 3-4 percentage points. The poor guy in the general public is getting a terrible product from the professionals. I think it's disgusting. It's much better to be part of a system that delivers value to the people who buy the product. But if it makes money, we tend to do it in this country.

I don't want to understand Facebook.

We like our current shareholders and don't want to entice anyone to become one. It would help current shareholders to hear our CEOs [of the Berkshireoperating subsidiaries], but we promised them they could spend 100% of their time on their business. We place no impediments on them running their businesses. Many have expressed to me how happy they are that they don't have to spend 25% of time on activities they didn't like.