In the prepared remarks, Zuckerberg said the company has a responsibility to make sure what happened with Cambridge Analytica doesn't happen again.
The Menlo Park, Calif., firm also unveiled a proposal to support academics who are researching the role that social media plays in democratic elections, including an independent peer-review process to oversee how scholars access "privacy-protected" data about Facebook users.
Facebook's press page was once filled with announcements about new features to order food and connect to friends in virtual reality.
About 214 million Americans with Facebook profiles do not know whether their data was among the information swept up for Cambridge Analytica.
He also detailed measures taken to limit how and what types of information third parties can collect about Facebook users and increased digital security and policing of rogue users to cut down on interference on elections.
"If we detect suspicious activity, we'll do a full forensic audit". Facebook spent $1.35 million on lobbying in 2011 and six years later spent $11.5 million, according to data maintained by the Center for Responsive Politics.
There were some pretty big flaws in Facebook's system (and Cambridge Analytica lied about what they were doing), which is why 311,000 Australians have had their data accessed by Cambridge Analytica, even though... we don't vote in...
Zuckerberg is also expected to be asked about Russia's use of US social media during the 2016 elections - a subject of several congressional investigations and special counsel Robert Mueller's probe into Russian interference.
Discussing his testimonies last week, Zuckerberg was vague when asked what topics would be of interest. Facebook says more than 70 million of the affected users are in the USA, though there are over a million each in the Philippines, Indonesia and the United Kingdom. "We are actually the product Facebook is marketing to other folks", said Pozner.
"I am very concerned about this breach of privacy and it's unacceptable", Peters said.
Zuckerberg, who founded Facebook in his Harvard University dorm room in 2004, is fighting to demonstrate to critics that he is the right person to go on leading what has grown into one of the world's largest companies. Dianne Feinstein, April 9, 2018 on Capitol Hill.
Facebook's previous emissary "was a silver-tongued devil" who "said nothing", Republican Senator John Kennedy said on CNBC on Monday.
Separately, Zuckerberg said in a Facebook post yesterday that the company is establishing an independent election research commission that will look into the effects of social media on elections and democracy. "Both of these trends will likely harm ad tech companies focused on buying media or otherwise focused on the Facebook and Google ecosystems".
In that list, users can see their political affiliation as well as other key phrases and demographics that Facebook has put the user into. Anticipating such a move, the company has already said it favors new legislation that would make social networks disclose who is behind political ads, much as TV and radio stations must already do. He said the "profits are all based on the user's info, but the users get none of the profits back".