After more than 10 years overseeing history's largest sociology experiment, Mark Zuckerberg has arrived at an important conclusion: Human beings are social animals who need communities to thrive.

It's hard to argue with that insight, but it's a strange one to have eluded Zuckerberg, founder of a social network comprising some two billion souls, for so long. But give him credit for coming by it honestly.

For the past few months, the Facebook CEO has been zipping around the United States, talking to folks about their lives and concerns. His big takeaway: Society is fraying because the "meaningful groups" in people's lives are disappearing. Small towns are emptying out; unions are closing up shop; Shriners' clubs aren't holding as many parades with the tiny cars and the fezzes.

"I'll go talk to people in a church, and a pastor will say, 'I know that when a factory closes down in town, I'll be doing marriage counseling with a lot of people in a month,'" Zuckerberg told Forbes's Kathleen Chaykowski. "Someone needs to do that, but that's happening less and less. People's support structures are going away."

Fortunately, Zuckerberg has the remedy. On Thursday, he announced a new corporate goal: Getting one billion Facebook users to join a "meaningful group," whether a Bible study circle, political action committee or victims' support network. Toward that end, Facebook is deploying a slew of new tools to make it easier for people to start and administer Facebook Groups, an existing feature most users currently aren't using.

Zuckerberg underscored the seriousness of his new commitment by changing Facebook's longstanding mission statement, from "Make the world more open and connected" to "Give people the power to build community and bring the world closer together."

The new formulation alludes to something that's been on Zuckerberg's mind at least since last November: the newfound political potency of isolationist movements around the world, and the role "fake news" and misleading partisan propaganda have played in their rise. In Zuckerberg's view, one function of meaningful groups is exposing members to people they can relate to but who may hold differing views. "We can help you connect over things that you share before exposing you to debates that are really important to have productively," he told Forbes.

If there's one criticism absolutely no one is leveling at Zuckerberg, it's that he doesn't talk enough about community. It's one of his totem words, along with "connect" and "build." However earnest he may be in his belief that a collection of people comprising more than one-quarter of the earth's population can constitute a "community" in any normal sense, it's also a handy way of punting responsibility for things like content standards: Rather than play censor, we'll let the community decide what's acceptable.

With Facebook's new focus on "meaningful groups," Zuckerberg is making a subtle but significant change in inflection, from emphasizing "our community" to emphasizing "your communities."

It's a step in the right direction, but far from a cure-all. Without a doubt, Facebook--and the internet in general--contributes to societal malaise by atomizing people, isolating them from the contexts that give them identity and comfort. Restoring some of that context is a good idea.

But Facebook also needs to take a hard look at how it shapes users' behaviors, whether as individuals or members of groups. The rewards, incentives and other nudges it uses to maximize engagement and promote sharing account for a lot of the distortions that make Facebook so problematic, whether it's the spread of false and ultra-partisan news, the fragmenting of attention spans or the insidious creeping rollback of personal privacy.

The more alienated Americans become from their institutions, the more they look to social media for a methadonic sense of solidarity. The more dysfunctional American politics gets, the more citizens take to their News Feeds to rail at each other. The slow collapse of civic institutions and public discourse has been massively profitable for Facebook. A sincere effort to reverse that breakdown may not be. How committed to that mission is Zuckerberg?