After five days of radio silence, Facebook CEO Mark Zuckerberg has finally apologised for a “major breach of trust,” admitted mistakes and has outlined steps to protect user data in light of the recent revelations made about the harvesting of personal data of 50 million users by a firm that was part of Donald Trump’s presidential campaign.

“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 added, “we don’t deserve to have the opportunity to serve people.”

His mea culpa on CNN came a few hours after he had made a public Facebook post about the issue, but he had stopped short of a public apology there.

Zuckerberg’s comments reflected the first time he apologized following an uproar over how Facebook allowed third-party developers to access user data. The CEO and company founder undertook a rare media tour with a handful of outlets to explain the company’s perspective on a scandal that has consumed the company since Friday.

Zuckerberg and Facebook’s No. 2 executive, Sheryl Sandberg, had been quiet since news broke Friday that Cambridge Analytica may have used data improperly obtained from roughly 50 million Facebook users to try to influence the US presidential elections and the UK’s Brexit referendum. Cambridge’s clients included Donald Trump’s general-election campaign, the UK’s Euro-sceptic Brexit camp and even Indian political parties like the BJP, Congress and the JD(U).

Facebook shares have dropped some 8%, shaving about $46 billion off the company’s market value, since the revelations were first published.

Here are some key highlights from the various interviews that Zuckerberg gave different media outlets:

  • While he told multiple outlets that he would be willing to testify before the US Congress with the added disclaimer that he’d do so only if it was “the right thing to do.” And added that many other Facebook officials might be more appropriate witnesses depending on what Congress wanted to know.
  • He said the company would notify everyone whose data was improperly used.
  • He was dicey on the issue of regulation, he told CNN, “I’m not sure we shouldn’t be regulated.” But he added that “There are things like ad transparency regulation that I would love to see.”
  • He admitted that Facebook was wrong for not investigating further when the Cambridge Analytica issue first came to light in 2015. “I think this was clearly a mistake in retrospect,” Zuckerberg told CNN. “We need to make sure we don’t make that mistake ever again.”
  • He insisted that Facebook could be protected from bad actors ahead of the United States’ midterm elections. “This isn’t rocket science. There’s a lot of hard work we have to do to make it harder for nation-states like Russia to do election interference,” he told CNN.
  • He told the New York Times that Facebook would double its security force this year. He said, “We’ll have more than 20,000 people working on security and community operations by the end of the year, I think we have about 15,000 now.”
  • He unveiled to NYT that the company had deployed new AI tools to fight bad actors in the recent Alabama Senate election: “With the special election in Alabama, we deployed some new A.I. tools to identify fake accounts and false news, and we found a significant number of Macedonian accounts that were trying to spread false news and were able to eliminate those.”
  • He told NYT that Facebook would investigate thousands of apps to determine whether they had abused their access to user data.
  • He further told NYT that a “meaningful number of people” had not deleted their accounts in the wake of the controversy. But he conceded, “I think it’s a clear signal that this is a major trust issue for people, and I understand that. And whether people delete their app over it or just don’t feel good about using Facebook, that’s a big issue that I think we have a responsibility to rectify.”
  • In his interview with Recode, he expressed regret for building a platform API that was vulnerable to abuse of the kind committed by Cambridge Analytica. “There was this values tension playing out between the value of data portability — being able to take your data and some social data, the ability to create new experiences — on one hand, and privacy on the other hand,” he said. “I was maybe too idealistic on the side of data portability, that it would create more good experiences — and it created some — but I think what the clear feedback was from our community was that people value privacy a lot more.”
  • He was sounded non-committal on the issue of content moderation, he told Recode, “[The] thing is like, ‘Where’s the line on hate speech?’ I mean, who chose me to be the person that did that?” He added though, “I guess I have to, because of where we are now, but I’d rather not.”
  • He told Wired that the company has not announced all the new restrictions coming to the platform yet, he said “There are probably 15 changes that we’re making to the platform to further restrict data, and I didn’t list them all, because a lot of them are kind of nuanced and hard to explain—so I kind of tried to paint in broad strokes what the issues are, which were first, going forward, making sure developers can’t get access to this kind of data.”