Zuckerberg testified before the U.S. Senate Commerce, Science and Transportation Committee on Tuesday.
Seemingly unimpressed, Republican Sen. "How is today's apology different?" He'll face House questioners Wednesday.
Butterfield waved a printout of Facebook's leadership as listed on its own website, "not you and Sheryl [Sandberg], but David [Wehner], Mike [Schroepfer], Chris [Cox]", all of whom are white.
The stakes are high for both Zuckerberg and his company.
By the time of the hearing's first break, Facebook's share price had risen by 5% - adding £3bn to his net worth. The time limit given to each representative mostly prohibited them from getting good detail from the Facebook founder. Ted Cruz, for instance, Zuckerberg was asked if he was ready to take a break.
The House hearing may prove no better. The Facebook CEO knows what his company does, but perhaps he couldn't acknowledge that his companies relies on assembling detailed dossiers on billions of people.
"Senator, we run ads", was the Facebook boss' response.
Facebook's chief executive has revealed that his data was among that harvested in a privacy scandal.
As for the federal Russia probe that has occupied much of Washington's attention for months, he said he had not been interviewed by special counsel Mueller's team, but "I know we're working with them". He was confident. He capably tackled many of the queries proposed last week by Bloomberg columnists. It goes to show you that even Mark Zuckerberg isn't safe from the monster he's created. "Nothing in life is free". Zuckerberg also fielded questions about the abuse of his platform by Russian troll-bots and purveyors of made-up clickbait stories.
Cantwell asked: "Do you think Palantir ever scraped data from Facebook?". He assured senators the company would handle the situation differently today.
Cambridge Analytica allegedly accessed users' personal data improperly and, according to a whistleblower, used that information to build psychological profiles to target voters with political ads.
Not so fast, the much older senators told Zuckerberg, 33, who was perched atop a seat pillow for the much-anticipated hearing into whether and how the breach affected the 2016 elections.
Republicans have yet to get behind any legislation, but that could change. If the user decides to protect that information, it is more of a case-by-case process.
Zuckerberg told a lawmaker during his appearance Wednesday he believes the notices about Cambridge Analytica's possession of their information began going out Monday. And as my Post colleague Anne Applebaum has noted, Zuckerberg seems agreeable to having the EU General Data Protection Regulation suggest changes to his site.
He outlined steps the company has taken to restrict outsiders' access to people's personal information.