"WhatsApp provides phone-number-based messaging, and people asked, 'Isn't that what SMS is?' Yes, but SMS is expensive, antiquated, and what WhatsApp did was modernize and level that playing field. For example, in Europe, if France wants to talk to Belgium, it's extraordinary costly because of border and telecom charges."

"It's not 100 per cent clear to me what's working about Snapchat."

"For me specifically, it was important to graduate. In my family, I was one of the first graduates. My mom did not have a college degree. My dad did not have a college degree."

"Going public is 18-month process, while an acquisition is a 6-month process. Going public means going under so much scrutiny, regulatory approval, auditing, magnified 10 times. Having the stomach to do that isn't necessarily in my DNA. My DNA is building a product and a service."

"My grandfather had two boys, my uncle had three boys, my dad had me and my two brothers, each of my brothers have had two boys. Then something happened with the chromosomal experiment and suddenly I've got three girls."

"Science fiction writers foresee the inevitable, and although problems and catastrophes may be inevitable, solutions are not."

"One of the first rules of science is if somebody delivers a secret weapon to you, you better use it."

"It is a remarkable honor to receive a Nobel Prize, because it not only recognizes discoveries, but also their usefulness to the advancement of fundamental science."