Mark Zuckerberg knew his keynote speech at F8 this year would not be like any other. His previous appearances at Facebook's annual developer's conference were all about the new products and technology Facebook was announcing that day, and the vision he would share for future triumphs.

But in the wake of Cambridge Analytica, fake news, Russian election-tampering, incendiary hate speech and did we mention Cambridge Analytica, Facebook has dished out serial apologies and embarked on a steady march of product adjustments and transparency initiatives, a course that is nowhere near completion. Zuckerberg understood that at this F8, he could not give short shrift to the near-existential crisis his company is undergoing. But he also didn't want to ignore the main function of F8—refilling the pipeline of new products and visions.

"The hardest decision this year hasn't actually been investing so much in safety and security," he says. "I mean, that was obvious—there was no choice to not do that. The real question is how do we also find a path to move forward on all the other things that our community expects from us."

Zuckerberg is telling me this as we meet offsite on the eve of F8, during his last-minute preparations for the event. We talked for almost an hour, discussing his keynote, some of the new products he's announcing, his feelings about his ten-hour congressional testimony, the question of whether the company censors conservative speech, the need to make Facebook more proactive in policing content, and why it will take three years to do it.

But first we talked about how he was going to thread a tiny needle on stage: rebuilding trust while also fulfilling the expectations of fans who want cool stuff and developers whose businesses depend on Facebook's continued evolution. "That's going to be what this whole conference is about," he says. "On the one hand the responsibilities around keeping people safe—the election integrity, fake news, data privacy and all those issues are just really key. And on the other hand, we also have a responsibility to our community to keep building the experiences that people expect from us. Part of the challenge of where we are is making sure that we take both seriously. F8 is going to be a balance of those two points."

The mea culpas come first. After the initial revelation of the Cambridge Analytica episode, which exposed the data of 87 million users, there was a five-day period when Zuckerberg and his operating partner Sheryl Sandberg were harder to find than the Golden State Killer, a mistake that Zuckerberg acknowledges. "We were initially very slow to respond," he says. "We were trying to understand all of the internal details around what happened. And I think I got this calculation wrong where I should have just said something sooner even though I didn't have all the details. Since we dug in and learned all of it, I think we're doing the right thing. It's just that we should've done it sooner."

In his keynote the plan is to acknowledge Facebook's problems and to introduce yet more features to address them. But he's also getting past the apologies. The dilemma he faces at F8 is a paradigm for his larger problem at Facebook. "The question isn't, do we feel bad. Of course we feel bad. But what we owe the world is, 'Here's what we're going do to make sure that doesn't happen [again].'"

Zuckerberg will then introduce one welcome new trust feature: the ability for users to wipe clean information that Facebook has gathered about them from their activities off Facebook, like web browsing. Zuckerberg compares this to cleaning the cookies out of one's browser, a form of digital hygiene that he occasionally practices himself. Apparently, this improvement was an indirect product of Zuckerberg's ten hours in the congressional hot seat last month. Zuckerberg tells me he had anticipated that the legislators' questions would largely focus on Cambridge Analytica and maybe the Russians, but instead they fired a broad range of questions at him, many of them involving the deep weeds of Facebook's operations.