Did he tell everything he knew?
A number of observers concluded that Zuckerberg generally handled the questioning well during his appearance before a joint meeting of the Senate Judiciary Committee and Senate Commerce, Science, and Transportation Committee.
House lawmakers aggressively questioned Zuckerberg Wednesday on user data, privacy settings and whether the company is biased against conservatives.
The data scandal wiped away tens of billions of dollars from Facebook's market value, prompted political scrutiny on both sides of the Atlantic and even raised the once unthinkable question of whether Zuckerberg should step down as CEO.
Mr Zuckerberg again demurred, saying: "I'm going to direct my team to focus on this".
"Every time there is a control right there", Zuckerberg said.
For instance, Rep. Chris Collins of NY asked Zuckerberg "what data was being collected" when Cambridge Analytica got its hands on the data of tens of millions of Facebook users in 2014.
The site has access to your data and can do with it whatever it pleases, as evidenced by the Facebook-Cambridge Analytica debacle.
Whether Facebook Messenger collects call and text data from minors for account syncing. He highlighted Harvard's dedication to protecting sensitive data, pointing to a almost 80-year-long study with participants including John F. Kennedy and the Unabomber, which never leaked.
Rep. Anna Eshoo (D-Calif.), who represents a Bay Area district that includes parts of Silicon Valley, asked, "Are you willing to change you business model in the interest of protecting individual privacy?"
Here's what Facebook says it tracks when you're not logged in: "We receive info about the web page you're visiting, the date and time and other browser-related info".
So to avoid getting left out of the next privacy breach, I'm adding a little more Red State to my Facebook data. And Facebook pays for security personnel and security systems at his residences, according to the filing.
Zuckerberg was called to testify following multiple news reports in recent weeks detailing how Facebook data was used without people's knowledge to target likely voters for President Donald Trump ahead of the 2016 election, drive misinformation campaigns by malicious actors in Russian Federation and elsewhere, and enable ethnic cleansing of the Rohingya people in Myanmar.
Also, whether Facebook keeps a backup version of your data after account shutdown.
The stolen data was so widespread that it even swept up information on Facebook CEO Mark Zuckerberg. He did argue, however, that "the average American uses eight different apps to communicate with their friends and stay in touch with people", including Twitter.
Facebook introduced the "Like" button for web pages in 2010.
Exactly how many fake accounts Facebook has shut down.
She later tweeted about plans to address Facebook algorithms in upcoming forums.
Why Facebook rejected a seemingly harmless advertising campaign by a state senator candidate from MI. "The content reviewers also go over flagged information". And yes, Facebook shouldn't have allowed itself to become Vladimir Putin's personal election-meddling tool.
Propose regulations to govern the tech industry.
Zuckerberg deflected requests to support specific legislation.
House lawmakers were a bit tougher on Zuckerberg than their colleagues in the Senate, many of whom seemed confused by the company and what it does.