Twitter is hard to evaluate. They have a lot of potential. It's a horribly mismanaged company — probably a lot of pot-smoking going on there. But it's such a solid franchise it may even work with all that.

Never invest in a tech CEO that wears a suit.

When you already have $150 billion a year in revenues from the iPhone, it's very hard to come up with any new vertical that will sort of move the dial. And there's this sort of weird effect where the larger a company gets, the harder it is to come up with any new product that really moves the dial.

I'm in favor of free trade, but I think if you had to make a choice between having technological progress versus free trade, you had one or the other, you should always pick technological progress. I think it's an incredibly important variable for creating more prosperity.

Rivalry causes us to overemphasize old opportunities and slavishly copy what has worked in the past.

You have as much computing power in your iPhone as was available at the time of the Apollo missions. But what is it being used for? It’s being used to throw angry birds at pigs; it’s being used to send pictures of your cat to people halfway around the world; it’s being used to check in as the virtual mayor of a virtual nowhere while you’re riding a subway from the nineteenth century.

We might describe our world as having retail sanity, but wholesale madness.