I would urge parents to limit the amount of social media that children can see because they're being programmed by a dopamine-maximizing AI.

If we're trying to build a world-class News Feed and a world-class messaging product and a world-class search product and a world-class ad system, and invent virtual reality and build drones, I can't write every line of code. I can't write any lines of code.

So I think that the scale of the systems has created this responsibility for us, where we have to be more proactive about finding and addressing issues [harmful content]. And we can do that both by building technology that is possible now, but wasn't even possible five or ten years ago, and by hiring people at a scale that would not have been possible for us before.

Open Graph is a language for structuring content and sharing that goes on in other apps, and we're continuing to build it out longer term. But we found we need to build more specific experiences around categories like music or movies. Where we've taken the time to build those specific experiences, stuff has gone quite well.

Facebook originally got started around the same time as a bunch of the early smartphones and those platforms got started. So we didn't really get to play any role in developing that platform.

We're at a point now where we've built AI tools to detect when terrorists are trying to spread content, and 99 percent of the terrorist content that we take down, our systems flag before any human sees them or flags them for us.