Our goal with fake news is not to prevent anyone from saying something untrue - but to stop fake news and misinformation spreading across our services.

What we will do is we'll say, 'Okay, you have your page, and if you're not trying to organize harm against someone, or attacking someone, then you can put up that content on your page, even if people might disagree with it or find it offensive.' But that doesn't mean that we have a responsibility to make it widely distributed in News Feed.

Our role is to be a platform for making all of these apps more social, and it's kind of an extension of what we see happening on the web, with the exception of mobile, which I think will be even more important than the web in a few years - maybe even sooner.

If something is spreading and is rated false by fact checkers, it would lose the vast majority of its distribution in News Feed. And of course if a post crossed line into advocating for violence or hate against a particular group, it would be removed. These issues are very challenging but I believe that often the best way to fight offensive bad speech is with good speech.

We started off as this platform inside Facebook; and we were pretty clear from the beginning that that wasn't where it was going to end up. A lot of people saw it and asked, 'Why is Facebook trying to get all these applications inside Facebook when the web is clearly the platform?' And we actually agreed with that.

Perhaps the loneliest time was during the Tata Tea issue in Assam. For some reason, everyone believed that we had conspired with the extremists, ULFA. People still believe what they read is necessarily the truth. Sometimes it is based on inadequate or wrong information.