After a riotous week full of revelations that Facebook enabled a shadowy British firm called Cambridge Analytica to harvest and exploit the personal information of more than 50 million users then failed to follow up on it for more than two years CEO Mark Zuckerberg offered an off-camera act of contrition Wednesday, yet no apology.

In the missive, Zuckerburg acknowledged theres been a breach of trust between Facebook and its users. He outlined several steps he hopes will restore public trust in the company, all aimed at clarifying and restricting which apps have access to which types of data.

Facebook also said it will investigate the apps on the platform that had access to large amounts of user data prior to 2014, before the company began limiting developers access. It plans to ban those found to be in violation of Facebooks terms and notify affected users, including those affected by Cambridge Analytica.

We have a responsibility to protect your data, and if we cant then we dont deserve to serve you, wrote Zuckerberg, who is scheduled to appear in an interview on CNN Wednesday night.

Notably, while Zuckerberg acknowledges Facebook made mistakes, his post stops short of anything resembling an apology.

Zuckerberg also failed to clarify how, exactly, Cambridge Analytica held onto and kept using the harvested data for a full two years after Facebook learned Cambridge had acquired it. He does offer the feeble defense that Facebook asked for, and received, a formal certification from the company verifying it deleted the data, but it was clearly insufficient.

In a separate post, Chief Operating Officer Sheryl Sandberg went a step further , stating she deeply regrets how Facebook handled Cambridge Analytica but again, its no apology.

You deserve to have your information protected and well keep working to make sure you feel safe on Facebook, she wrote. Your trust is at the core of our service. We know that and we will work to earn it.

Its been a response several days in the making, as neither Zuckerberg nor Sandberg offered so much as a peep earlier this week as the allegations piled up and Facebooks stock tanked .

Both were absent from an internal briefing about the situation Tuesday (though they were never scheduled to appear in the first place). And while Zuckerberg was expected to speak at an all-hands meeting Friday, it seems thats been bumped up a day or two.

Translation of Zuckerbergs Wednesday post: He is super serious, you guys. This time, he promises itll be different.

Not like last time, in September, when he appeared before cameras and pledged Facebook would do a better job self-regulating and create a new standard for transparency in online political ads.

(That particular acknowledgment was only prompted by the revelation that more than half of all eligible voters in the U.S. were exposed to and interacted with Russian propaganda on Facebook between June 2015 and August 2017.)

Or the time before that, in July 2017, when a Facebook spokesperson flat-out told CNN we have seen no evidence that Russian actors bought ads on Facebook in connection with the election.

(Just two weeks later, Facebook revealed it had found more than 3,000 such ads , bought and paid for by a Russian group known as the Internet Research Agency.)

Or the time before that, in November 2016, when Zuckerberg dismissed as crazy the idea that misinformation, spread via Facebook, could have influenced the election in any way.

(Then-President Barack Obama reportedly pulled Zuckerberg aside a couple of days after he made the statement and warned he should take the threat of disinformation on the network seriously. About a year after Obamas warning, Zuckerberg wrote a mea culpa saying he regretted the statement. This is too important an issue to be dismissive, he said.)

Or the time before that, during the first Democratic primary of 2016, when Roger McNamee, an early Facebook investor, said he warned Zuckerberg and Sandberg that people were being manipulated on the platform yet his concerns went unheeded .

They treated it like a public relations problem, rather than a substantive issue for the business, he said, in a statement thats just as relevant today as it was then.

Facebook has forcefully argued its fine policing itself since at least 2011, when the Federal Election Commission first considered regulating political ads on the platform, then backed down after being warned by company lawyers not to stand in the way of innovation.

Making you angry, making you afraid, is really good for Facebooks business, McNamee said previously. It is not good for America. Its not good for the users of Facebook.

This post has been updated with Sandbergs Wednesday statement and more background on Facebooks history.