Fact-checking Facebook CEO Mark Zuckerberg's congressional testimony

Mark Zuckerberg, the 33-year-old billionaire founder of Facebook, wound up two days of hearings on Capitol Hill, explaining the company’s policies and the role it had in the 2016 election. The questions from House members were more pointed than those from senators the day before, but the themes of privacy and regulation were about the same.

While Zuckerberg’s answers generally hewed to the literal truth, they also tended to omit some key details. We spoke with social media investors, academic analysts and privacy advocates to evaluate his testimony.

Cambridge Analytica, a data mining firm used by the 2016 Trump campaign, had obtained between 50 million and 87 million Facebook user profiles harvested by a Facebook-approved app, most without the users’ consent. That privacy breach is what led to Zuckerberg’s appearance.

Roger McNamee, the co-founder of the private equity group Elevation Partners and an early Facebook investor, said that while people might be focused on Cambridge Analytica, "the scope of the problem is huge." Many developers, McNamee said, were dipping into users’ friends lists to reach new people, and that fed directly into Facebook’s business plan.

"This was not the result of what one researcher did, consciously misleading users about the information they were sharing," McNamee said. "It was vital to have access to friend lists. This increased the number of minutes of use per day which made the advertising more valuable for Facebook."

It’s worth noting that while Facebook started taking action in 2014 to block user profile harvesting, it wasn’t until 2015 that the changes were fully in effect.

Brian Wieser, an analyst at Pivotal Research, said that even with the fully implemented changes, "there is still a lot of personal data that is used in the targeting of ads and delivery of content."

Zuckerberg offered versions of this statement to bolster his point that "you control your information." But Zuckerberg skips over what users can’t control, said Alex Howard, deputy director of the Sunlight Foundation, an advocacy group that helped craft the Honest Ads Act aimed at online campaign advertising said.

"There's a difference between what you are putting into Facebook and what Facebook is collecting about you," Howard said. "You can see your profile. But you only have access to the content you put on the platform. You can take down your photos, but not the record of who reacted to them. Not the metadata, not your search history, or your activity stream."

All of that data helps Facebook target ads, which keeps it profitable.

Facebook also has information on people who aren’t registered with Facebook. For the first time, Zuckerberg publicly acknowledged that it does have that data. As one lawmaker noted, the website’s directions for how to control that data require the person – who isn’t on Facebook – to go to their Facebook page.

Zuckerberg said user ownership of content is fundamental to the website. But the emphasis on informed and empowered users masks an important dynamic, said Woodrow Hartzog, professor of law and computer science at Northeastern University. There’s a gap between what the company allows you to do, and what it encourages you to do.

"Platforms like Facebook have overwhelming incentives to extract the maximum amount of value and data out of us," Hartzog said. "Facebook can engineer your consent to all kinds of data practices though obfuscated buttons, vague, abstract language, and a ceaseless stream of nudges, reminders, and efficiencies to get you to share."

Sen. Lindsey Graham, R-S.C., pressed Zuckerberg on Facebook’s market power. Zuckerberg said that people have choices and that he doesn’t feel that the company enjoys a monopoly.

Research suggests that smartphone users may utilize about nine apps per day. The list includes Twitter, Snapchat and LinkedIn. But some of the most popular apps, such as Whatsapp and Instagram, are owned by Facebook.

If Zuckerberg downplayed Facebook’s dominance, researchers did not.

"This is not an ordinary company, not a company of a sort we've seen before," said  University of Colorado media studies professor Nathan Schneider. "It dominates the markets for news distribution and advertising, and many people have no meaningful choice over whether to use it."

Facebook’s Messenger Kids allows children between 6 and 12 to send texts and videos as an extension of a parent’s account. When asked what would happen to the data of the child’s usage, Zuckerberg said kids that moved on to create their own Facebook accounts would start from scratch.

Josh Golin, executive director of the Campaign for a Commercial-Free Childhood, said he’s not sure that’s the full story.

"He didn’t answer – and Facebook has never answered – whether Facebook will retain all the data that was collected before a child was 13 and use it for advertising purposes once a child turns 13," Golin said.

In 2011, Facebook and the FTC agreed that the company would get users’ clear permission before sharing their information with any third party. The data Cambridge Analytica gathered was collected in 2014.

For the Electronic Privacy Information Center’s  Marc Rotenberg, Zuckerberg’s statement raises significant questions.

"He has yet to say what precisely Facebook did after the 2011 consent order to improve privacy protections for Facebook users," Rotenberg said. "Every statement points to changes that occurred much later, in 2014 or 2015."

The FTC is investigating whether Facebook fully complied with the order it signed.