Facebook used to repeat its mission statement so often that most tech reporters could recite it from memory: “To give people the power to share and make the world more open and connected.” And it’s still the mission you see when you visit the company’s Facebook page. But in a remarkable letter published today, CEO Mark Zuckerberg acknowledged the severe shortcomings and blind spots that his company’s mission created. Going forward, he said, the company will consider what happens after it connects people — and try to manage those effects for the better. “In times like these,” Zuckerberg wrote, “the most important thing we at Facebook can do is develop the social infrastructure to give people the power to build a global community that works for all of us.”

Over 5,800 words, Zuckerberg mentions “social infrastructure” 14 times — without ever quite describing what it is. But at a high level, he writes, he has five goals: to help users build communities that are supportive, that are safe, that are informed, that are civically engaged, and that are inclusive. “For the past decade, Facebook has focused on connecting friends and families,” Zuckerberg writes. “With that foundation, our next focus will be developing the social infrastructure for community.”

“Our next focus will be developing the social infrastructure for community.”

Safe, supportive, and inclusive communities should be table stakes for any social networking app, and Facebook has arguably done better on those fronts than many of its peers. It still has plenty of work to do: Zuckerberg described plans to invest more heavily in its Groups product, offer resources to users considering self-harm, and provide more granular content settings to reflect local attitudes.

It’s the piece about making users more informed and civically engaged where Facebook promises to break new ground. The company has been battered in the press since last year’s presidential election, when hoaxes and misinformation spread virally on the platform and likely contributed to Donald Trump’s surprise victory. Zuckerberg was initially dismissive of the idea that Facebook played a role in the election, calling the idea “crazy.”

He has clearly done a lot of thinking since then. In his letter, Zuckerberg repeats previous statements saying the company should do more to combat misinformation. But he then shifts to discussing the way social platforms lead to polarized user bases. It’s worth quoting in full:

Social media is a short-form medium where resonant messages get amplified many times. This rewards simplicity and discourages nuance. At its best, this focuses messages and exposes people to different ideas. At its worst, it oversimplifies important topics and pushes us towards extremes. Polarization exists in all areas of discourse, not just social media. It occurs in all groups and communities, including companies, classrooms and juries, and it's usually unrelated to politics. In the tech community, for example, discussion around AI has been oversimplified to existential fear-mongering. The harm is that sensationalism moves people away from balanced nuanced opinions towards polarized extremes. If this continues and we lose common understanding, then even if we eliminated all misinformation, people would just emphasize different sets of facts to fit their polarized opinions. That's why I'm so worried about sensationalism in media.

Here Zuckerberg is finally reckoning with the most uncomfortable truth about the world’s largest social network. As it has grown to 1.86 billion users, Facebook has pushed us to more extreme political viewpoints. It is not alone in this: talk radio, cable television, newspapers, and Twitter have all played their part. But because of its scale, Facebook’s contribution to the problem is exponentially greater. And Zuckerberg, to his credit, seems determined now to address it.

Finally reckoning with the uncomfortable truth

He talks about providing users with a range of perspectives, rather than presenting “both sides” — a tactic that generally increases polarization. He talks about identifying user behaviors that signal an article shared on Facebook is sensational, and then using those signals to dampen the article’s viral spread. And he writes about ensuring that the users he hopes to inform will then participate in democracy, starting with voting and continuing into experiments around community governance.

In 2015, when Facebook’s status as the most important media distributor in the world was already clear, I called on Facebook to edit its mission statement to reflect its responsibility to make users more informed. “Zuckerberg has spent years talking about Facebook as the next evolution of the newspaper,” I wrote. “But to really be the heir to the newspaper, your mission can’t stop at ‘making the world more open and connected.’ You have to make the world smarter, too.”

In 2016, a world that Facebook made no smarter brought itself to the brink of catastrophe. Today, in a press conference, the president raised the possibility of nuclear Holocaust. Brexit, Trump, and a global assault on democracy were propelled forward by polarization, sensationalism, and misinformation — all of which found a welcome home on Facebook. I’m glad Facebook will now assume some responsibility for the effects its platform is having on the world. But I will never stop asking what might have been had it taken responsibility sooner.