The First Amendment protects our right to use social networks like Facebook and Twitter, the Supreme Court declared last week. That decision, which overturned a North Carolina law barring sex offenders from social networks, called social media “the modern public square” and “one of the most important places” for the exchange of views. The holding is a reminder of the enormous role such networks play in our speech, our access to information and, consequently, our democracy. But while the government cannot block people from social media, these private platforms can.

In some ways, online platforms can be thought of as the new speech governors: They shape and allow participation in our new digital and democratic culture in ways that we typically associate with governments. Even Facebook’s recently updated mission statement acknowledges this important role, with its vow to give “people the power to build community and bring the world closer together.” But social media sites are not bound by the First Amendment to protect user speech. Facebook’s mission statement says as much, with its commitment to “remove bad actors and their content quickly to keep a positive and safe environment.”

Until recently, the details of the types of posts Facebook prohibited were a mystery. That changed on May 21 when The Guardian released over 100 pages of leaked documents revealing Facebook’s internal rules. This newfound transparency could mean Facebook will be held accountable to the public when it comes to its decisions about user speech.

Facebook has often been pressured to explain or alter its approach to moderating users’ speech, in cases involving topics like breast feeding pictures, Donald Trump’s posts about banning Muslims from entering the United States and the video of a Cleveland murder. But before this leak, nobody outside the company could say exactly how it made decisions — and it was under no legal obligation to share.