Senator Bill Nelson: "Let me just cut to the chase". Mark Zuckerberg's hearing will continue on Tuesday and we will bring you the updates.
His opening statement closely mirrored prepared remarks that circulated Monday.
"In retrospect I think that was a mistake and knowing what we know now we should have handled a lot of things here differently", he said.
But he said he tries to make sure Facebook does not have any bias in the work that it does.
Zuckerberg was testifying before the US Senate after a firestorm erupted over Facebook's alleged failure to protect its users' data.
Her friend, Ali Neiland says she now plans on changing and updating her privacy settings.
First, from now on, every advertiser who wants to run political or issue ads will need to be verified.
Cambridge Analytica used the data to illegally create "psychographic" profiles and delivered the content online.
Facebook plans to reveal all the third-party apps that have authorization to access user data, the company said. He said his company will propose regulations it considers appropriate. Roger Wicker, R-Miss.
"We've seen the apology tours", scoffed Democratic senator Richard Blumenthal of CT. "If I'm upset with Facebook, what's the equivalent product I can go sign up for?" asked Graham.
He did not rule out a subscription model but said Facebook would always offer a free service to reach the broadest possible audience.
Separately, the company began alerting some of its users that their data was gathered by Cambridge Analytica.
Facebook scans pictures and texts that users send each other on its Messenger app "to ensure they are in line with Facebook's community standards", Mr Zuckerberg confirmed.
Referring to recent elections in Germany, France, and Albaman, the Facebook owner said, "I have more confidence we'll get this right because since the 2016 election, there have been several important elections around the world where we've had a better track record". Zuckerberg has been on an apology tour for most of the past two weeks, culminating in his congressional appearance Tuesday.
Facebook, he said, do not generally ask people about their political orientation when they're joining the company.
There are some questions that seem to leave even Zuckerberg perplexed.
- Useful to find someone by phone number/email; if people have the same name.
It's this pose that makes him and other Facebook officials sound so shifty.
Zuckerberg has been unclear about whether Facebook would extend the European protections to the US and elsewhere.
During the session, Facebook also received questions about Artificial Intelligence (AI) which the company utilises.
Day one of the testimony has concluded but will continue Wednesday and we expect more details from Zuckerberg on the action taken by the company on the data breach.
In the hearings, Zuckerberg is trying to both restore public trust in his company and stave off federal regulations that some lawmakers have floated. "I think it's pretty much impossible, I believe, to start a company in your dorm room and then grow it to be at the scale that we're at now without making some mistakes".
"Your user agreement sucks", Republican senator John Kennedy of Louisiana told Zuckerberg with characteristic bluntness. "We'll pay the person who reported the issue, and we'll also alert those we believe to be affected".