Well how do you sustain a business model in which users don't pay for your service? Senator, we run ads. [MUSIC] If I'm emailing within WhatsApp, does that ever inform your advertisers? No, we don't see any of the content in WhatsApp, it's fully encrypted. Right, but is there some algorithm that spits out some information to your ad platform and then let's say I'm emailing about Black Panther within WhatsApp, do I get a WhatsApp- Do I get a Blank Panther banner ad? [MUSIC] Senator, we don't, Facebook systems do not see the content of messages being transferred over WhatsApp. Yeah I know, but that's not what I'm asking. I'm asking about whether these systems talk to each other without a human being touching it. Senator, I think the answer to your specific question is, if you message someone about Blank Panther in WhatsApp, it would not inform. Any ads. Okay, there have been reports that Facebook can track a user's Internet browsing activity even after that user has logged off of the Facebook platform. Can you confirm whether or not this is true? [MUSIC] Senator, I, I want to make sure I get this accurate, so it would pobably be better to have my team follow up afterwards. You don't know? I know that the people use cookies on the Internet, And that you can probably correlate activity between sections. We do that for a number of reasons including security and including measuring ads to make sure that the ad experiences are the most effective which, of course, people can opt out of Will Facebook offer to all of its users a blanket opt-in to share their privacy data with any third-party users? Congresswoman, yes. That's how our platform works. You have to opt in to sign in to any app before you use it. Could somebody call you p and say, I wanna see John Kennedy's file? Absolutely not. Could you, not would you do it. Could you do it? In theory. Do you have the right to put a name on my data and share it with somebody? I do not believe we have the right to do that. Do you have the ability? Senator, the data is in the system so- Do you have the ability? Technically, I think someone could do that. But that would be a massive breach. So we would never do that. [MUSIC]