Veronica Rocha, Brian Ries and Amanda Wills, CNN
YOUR QUESTIONS, ANSWERED
Facebook CEO Mark Zuckerberg "is not being sworn-in under oath, but he still has a legal obligation to testify truthfully," a Commerce committee GOP aide tells CNN. "By tradition, the Commerce Committee does not swear-in witnesses," the aide added.
From CNN's Daniella Diaz
During his round of questioning, Sen. Lindsey Graham asked Mark Zuckerberg if he thought Facebook was a monopoly.
"It certainly doesn't feel like that to me," Zuckerberg said.
That response drew some light laughter from some in the room.
Sen. Maria Cantwell, a Democrat from Washington, quizzed Facebook CEO Mark Zuckerberg today over his employees' dealing with Cambridge Analytica, a political data firm with ties to President Donald Trump's campaign.
Asked whether Facebook employees were involved with Cambridge Analytica during the 2016 presidential campaign, Zuckerberg said he didn't know, though they did "help out."
"Although, I know we did help out the Trump campaign overall in sales support in all in same way that we help do with all other campaigns," he said.
Why we're talking about Cambridge Analytica
Last week, Facebook said Cambridge Analytica may have had information on about 87 million Facebook users without the users' knowledge. Previous reporting had put the number of users at about 50 million.
The data obtained was originally collected by University of Cambridge professor Aleksandr Kogan who used an app called "thisisyourdigitallife," which offered a personality test. Facebook users who downloaded the app granted it permission to collect data on their location, friends and things they Liked. The data collection was allowed by Facebook at the time.
However, Facebook has said that Kogan violated its terms of service by giving the information to Cambridge Analytica.
Facebook banned Kogan and Cambridge Analytica from its platform last month ahead of a New York Times investigative report about how the data was passed on.
Facebook CEO Mark Zuckerberg confirmed that special counsel Robert Mueller's team has interviewed the Facebook staff about Russian meddling in the 2016 election.
Zuckerberg said his employees have spoken to the Mueller team, but he has not personally been interviewed.
"I want to clarify, I'm not sure we have subpoenas. I know we're working with them," Zuckerberg said.
CNN reported in September that Facebook handed Russia-linked ads over to Mueller under a search warrant.
Codepink demonstrators held signs before a joint hearing of the Senate Judiciary and Commerce Committees with Mark Zuckerberg that read, "Protect our privacy," "Stop corporate spying," and — in a literal sign they weren't joining the #DeleteFacebook movement — "Like us on Facebook."
From CNNMoney's Paul R. La Monica
Shares of Facebook, which were up about 2% when the hearing began, moved even higher as Zuckerberg addressed questions from senators.
The stock was up nearly 5% by 3:20 p.m. ET, a sign that investors seemed to be impressed with Zuckerberg's answers — and maybe a little less concerned that more federal regulations would be imposed on it and rival tech companies.
Other social media stocks, rallied too. YouTube owner Google was up nearly 2%, and Twitter surged 7.5%.
Sen. Dianne Feinstein just asked Mark Zuckerberg what Facebook was doing to prevent foreign actors from interfering in US elections?
He said it is one of his "top priorities" to "get this right," and that he truly regrets what happened in 2016. "This is one of my top priorities is to get this right. One of my greatest regrets is we were slow in identifying the Russian operations in 2016," Zuckerberg said.
Sen. Bill Nelson, a Democrat from Florida, asked whether Facebook is considering forcing Facebook users to pay to block unwanted advertisements
Facebook CEO Mark Zuckerberg said its users have control over their ad experience and they can turn off third-party information.
"To be clear, we don't offer an option today for people to pay not to show ads," Zuckerberg said. "We think offering an ad-supported service is most aligned with our mission of trying to connect everyone in the world because we want to offer a free service that everyone can afford."
He said in the first line of Facebook's terms of service, they tell users that they control and own the information and content that's on their Facebook.
From CNN's Seth Fiegerman
The appearance marks the first time that Zuckerberg has testified before Congress. Zuckerberg, 33, swapped his usual gray t-shirt and jeans attire for a dark blue suit and light blue tie.
He appeared somber as he walked in to testify, and spoke before a packed room, with 44 senators in attendance.
"It's extraordinary to hold a joint committee hearing. It's even more extraordinary to have a single CEO testify before nearly half the United States Senate," said Sen. John Thune, chairman of the Commerce Committee.
"Then again, Facebook is extraordinary."
