The best entrepreneurs know this: every great business is built around a secret that’s hidden from the outside. A great company is a conspiracy to change the world; when you share your secret, the recipient becomes a fellow conspirator.

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.

I'm always very excited about trying to do something on next-generation biotechnology and life sciences because I think if we can cure cancer or dementia, we can really make the future a lot better and I think these things are eminently doable.

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

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.

Brilliant thinking is rare, but courage is in even shorter supply than genius.

Distribution may not matter in fictional worlds, but it matters in most. The Field of Dreams conceit is especially popular in Silicon Valley, where engineers are biased toward building cool stuff rather than selling it. But customers will not come just because you build it. You have to make this happen, and it's harder than it looks.