How and Why Internet Companies Moderate Speech Online

When the World Wide Web opened for public use in 1991, its enthusiasts proclaimed a new era of unfiltered free expression. Thirty years later, the debate is over how, not whether, to filter what’s said online. In the U.S., home to the biggest social media companies, Facebook Inc. is under particular scrutiny over which content it silences, and which it amplifies, as moderator of a discussion involving 1.9 billion people on a typical day.

The First Amendment to the U.S. Constitution prohibits censorship by government, not censorship by private companies like those that run social media platforms. In fact, those companies enjoy First Amendment privileges of their own. Like newspapers, book publishers and television stations, they have constitutional protections to decide on their own what to moderate and filter. And Section 230 of the Communications Decency Act of 1996 gives them broad protection from the kinds of liability publishers traditionally face for defamatory content, along with broad leeway to moderate discussions and remove posts or leave them alone.