The fact that the current United States president used this data to help secure an election win is pretty scary, and a lot of people want the use of this information restricted and regulated to stop us from becoming a real life Black Mirror episode.
"We didn't focus enough on preventing abuse and thinking through how people could use these tools to do harm as well", Zuckerberg told reporters on a media call.
"We didnt take a broad enough view of our responsibility, and that was a big mistake". It was a way of arguing that Facebook was not responsible for the user-created content on the site.
He is set to appear before a joint hearing of the Senate Judiciary and Commerce committees on Tuesday afternoon followed by a House Energy and Commerce Committee hearing on Wednesday morning. Yesterday, he met privately with the leaders of the Senate committees.
The hearings were scheduled to address Facebook's use and protection of user data in the wake of the Cambridge Analytica scandal.
"My top priority has always been our social mission of connecting people, building community and bringing the world closer together", Zuckerberg's prepared remarks say.
Zuckerberg is also expected to be asked about Russia's use of USA social media during the 2016 elections - a subject of several congressional investigations and special counsel Robert Mueller's probe into Russian interference. Facebook said it was still auditing CubeYou, which is based in Redwood City, Calif., but believed it could suspend as many as 50 apps from the company.
"We will do our part not only to ensure the integrity of free and fair elections around the world, but also to give everyone a voice and to be a force for good in democracy everywhere".
If anyone was concerned about apps misusing their data, the best option was "not to use them in first place", by not downloading them or not logging into apps with Facebook account details, he said. "Advertisers and developers will never take priority over that as long as I'm running Facebook", he said in his prepared remarks. He also said the company is investigating every app that had access to a large amount of information before the company moved to prevent such access in 2014 - something that came too late in the Cambridge Analytica case.
This is just the first of two official testimony appearances Zuckerberg will make on Capitol Hill this week.
"My personal opinion of him was he was forthright and honest to the degree that he could". "I expect members of Congress are going to grill him intensely and if they feel like they aren't getting straight answers they are going to lose their patience pretty quickly", he said.
Federal law, he said, hasn't kept pace with the still-emerging technology, he said.
Republicans so far have shown little appetite for such regulation, but that could change if there are future privacy scandals or Democrats gain control of Congress in this November's elections.
Zuckerberg goes before the House Commerce and Energy Committee on Wednesday.
Although Zuckerberg will likely continue to blame "bad actors" misusing the platform, it will be hard to deflect questions about Facebook's core business model of continually tracking and monetising individuals and their relationships.
"In consultation with the foundations funding the initiative, Facebook will invite respected academic experts to form a commission which will then develop a research agenda about the impact of social media on society - starting with elections", a company statement said.