People are good at figuring out what's attractive, and computers are good at quickly searching and finding. You put them together, and bang!

I usually make to-do lists with timelines, and pen and paper does the trick for me.

Before the Internet, coordinating more than 100,000 people, let alone paying them, was essentially impossible. But now with the Internet, I've just shown you a project where we've gotten 750 million people to help us digitize human knowledge.

I worked on a number of projects that were used by millions of people and that also served as inspiration to what we now call "crowd-sourcing."

People are good at figuring out what's attractive, and computers are good at quickly searching and finding. You put them together, and bang!

One fact we're particularly proud of is that there are more people learning languages on Duolingo in the US than there are people learning languages in the entire US public school system.

Every time you buy tickets on Ticketmaster, you help to digitize a book.