Facebook CEO Mark Zuckerberg this week made a historic concession about how his service should be governed. In an interview with Vox’s Ezra Klein, he asked, “How can you set up a more democratic or community-oriented process that reflects the values of people around the world?” Mr. Zuckerberg went further, saying Facebook users dissatisfied with the company’s decisions about what content is permissible should be able to appeal to something like a “supreme court,” whose judges didn’t work for Facebook.

He is on to something. There might be a way to counter the undue social power of this company, whose 2.2 billion users represent the largest aggregation of people ever assembled for any purpose. An independent oversight body, working in partnership with Facebook, could be created with the responsibility of advising and even making decisions about content and company behavior that otherwise would inevitably be based on commercial considerations.