The message growth rate in Brazil - it's not like a hockey stick: it's like a vertical line.

WhatsApp's extremely high user engagement and rapid growth are driven by the simple, powerful and instantaneous messaging capabilities we provide.

In some ways, you can think of end-to-end encryption as honoring what the past looked like.

People have SMS, right? It stinks. It's a dead technology, like a fax machine left over from the Seventies, sitting there as a cash cow for carriers.

Our phones are so intimately connected to us, to our lives. Putting advertising on a device like that is a bad idea. You don't want to be interrupted by ads when you're chatting with your loved ones.

When I was a kid trying to communicate with family in the Soviet Union, it was very difficult. You had to go through the long-distance phone companies like MCI, which were difficult to navigate and expensive to make calls through.