Facebook was about connecting with people — family, friends, old high-school exes.

As of Thursday, it's about saving the world.

That's what Mark Zuckerberg announced in a 6,000-word manifesto detailing how Facebook will look to create the "infrastructure" that will help solve some of the world's biggest problems.

Yes, really.

"Our job at Facebook is to help people make the greatest positive impact while mitigating areas where technology and social media can contribute to divisiveness and isolation," Zuckerberg wrote. "Facebook is a work in progress, and we are dedicated to learning and improving. We take our responsibility seriously, and today I want to talk about how we plan to do our part to build this global community."

The sudden announcement comes at a time when Facebook has been under near-constant criticism for its role in spreading misleading and outright false news, as well as broader questions about the social network's value.

Zuckerberg himself has also been the subject of some of the bad press, particularly for downplaying the social network's role in disseminating "fake news" — something he had mostly dodged up until recently.

The post appeared to serve primarily as a new strategic north star for Facebook, teasing that the social network could soon begin rolling out features not necessarily in line with its goal of connecting people.

It could also mark a major change in how Zuckerberg sees Facebook. Previously, the company had mostly been passive. Now, the company could be on its way to being more active.

Zuckerberg also seemed to have put Facebook in opposition to growing nationalist sentiments around the world that are pushing for a new era of isolationism.

"Progress now requires humanity coming together not just as cities or nations, but also as a global community," he wrote.

In the lengthy post, Zuckerberg pointed to questions around five main areas: "Supportive communities," "safe community," "informed community," "civically-engaged community," and "inclusive community."

Those are the key areas that Zuckerberg said Facebook will focus on to make the world a better place.

"There are many of us who stand for bringing people together and connecting the world. I hope we have the focus to take the long view and build the new social infrastructure to create the world we want for generations to come," he wrote.

As for concrete steps on what Facebook will actually do to achieve that, there's not many.

Under "supportive communities," Zuckerberg detailed a new way to measure success for Facebook, as well as noting that strengthening communities offline is an important part of the company's new direction.

He also specified "meaningful groups" as being worth extra attention, using parental groups as an example.

"Going forward, we will measure Facebook's progress with groups based on meaningful groups, not groups overall. This will require not only helping people connect with existing meaningful groups, but also enabling community leaders to create more meaningful groups for people to connect with," he wrote.

Under "safe community," Zuckerberg highlighted Facebook's efforts to develop artificial intelligence that can scan posts and tell the difference between news and propaganda.

"Right now, we're starting to explore ways to use AI to tell the difference between news stories about terrorism and actual terrorist propaganda so we can quickly remove anyone trying to use our services to recruit for a terrorist organization. This is technically difficult as it requires building AI that can read and understand news, but we need to work on this to help fight terrorism worldwide," he wrote.

Under "informed community," Zuckerberg teased that Facebook is working on ways to help support journalism — something that has yet to seriously materialize.

"There is more we must do to support the news industry to make sure this vital social function is sustainable -- from growing local news, to developing formats best suited to mobile devices, to improving the range of business models news organizations rely on," he wrote.

Under "civically-engaged community," Zuckerberg said that Facebook is well positioned to help boost public participation in local politics.

"In the last few months, we have already helped our community double the number of connections between people and our representatives by making it easier to connect with all our representatives in one click," he wrote.

Under "inclusive community," Zuckerberg teased perhaps the biggest change — more customization in personal settings.

"The idea is to give everyone in the community options for how they would like to set the content policy for themselves. Where is your line on nudity? On violence? On graphic content? On profanity? What you decide will be your personal settings," he wrote.

And, at the end, he quoted Abraham Lincoln.

"I am reminded of President Lincoln's remarks during the American Civil War: 'We can succeed only by concert. It is not 'can any of us imagine better?' but, 'can we all do better?' The dogmas of the quiet past, are inadequate to the stormy present. The occasion is piled high with difficulty, and we must rise with the occasion. As our case is new, so we must think anew, act anew.'"