Beginning with brand rather than substance is dangerous.

In a world where wealth is growing, you can get away with printing money. Doubling the debt over the next 20 years is not a problem.

The college kids should think hard about what they're doing. If you have a great idea for a company, there's no right time to start it, and it's often better to start it sooner rather than later. I went to Stanford undergrad and Stanford Law School, and if I had to do it over again, I might still do those things, but I wish I had asked the type of questions like, why I was doing it, was it just for the status and prestige, or was it because I was really interested in the substance of it.

Of the six people who started PayPal, four had built bombs in high school.

For a new payment product, you always have to ask, how much better is it than the current solution? So when we started Paypal, for eBay micro merchants, it was much better than getting the 7 to 10 days process of cashing a check in the mail. When you look at stores or physical worlds, places, a lot of these places are already set up to take cash or credit card. Apple Pay may be an incremental improvement, maybe a little bit better. But when you have something that's pretty good and you go to something that's perfect, sometimes it's very hard to drive adoption because the delta is not that big.

Great tech opportunities happen only once.

The zero-sum world [the movie The Social Network] portrayed has nothing in common with the Silicon Valley I know, but I suspect it's a pretty accurate portrayal of the dysfunctional relationships that dominate Hollywood.