"I am really sorry that happened," Zuckerberg said of the scandal involving data mining firm Cambridge Analytica. Facebook has a "responsibility" to protect its users' data, he said in a Wednesday interview on CNN. If it fails, he said, "we don't deserve to have the opportunity to serve people."
His mea culpa on cable television came a few hours after he acknowledged his company's mistakes in a Facebook post , but without saying he was sorry.

Zuckerberg and Facebook's No. 2 executive, Sheryl Sandberg, had been quiet since news broke Friday that Cambridge may have used data improperly obtained from roughly 50 million Facebook users to try to sway elections. Cambridge's clients included Donald Trump's general-election campaign.

Facebook shares have dropped some 8 percent, lopping about $46 billion off the company's market value, since the revelations were first published.