The article is here; here are the Introduction and the start of Part I:
Current approaches to content moderation generally assume the continued dominance of "walled gardens": social-media platforms that control who can use their services and how. Whether the discussion is about self-regulation, quasi-public regulation (e.g., Facebook's Oversight Board), government regulation, tort law (including changes to Section 230), or antitrust enforcement, the assumption is that the future of social media will remain a matter of incrementally reforming a small group of giant, closed platforms. But, viewed from the perspective of the broader history of the Internet, the dominance of closed platforms is an aberration. The Internet initially grew around a set of open, decentralized applications, many of which remain central to its functioning today.
Email is an instructive example. Although email is hardly without its content-moderation issues—spam, in particular, has been an ongoing problem—there is far less discussion about email's content-moderation issues than about social media's. Part of this is because email lacks some of the social features that can make social media particularly toxic. But it is also because email's architecture simply doesn't permit the degree of centralized, top-down moderation that social-media platforms can perform. If "ought" implies "can," then "can't" implies "need not." There is a limit to how heated the debates around email-content moderation can be, because there's an architectural limit to how much email moderation is possible. This raises the intriguing possibility of what social media, and its accompanying content-moderation issues, would look like if it too operated as a decentralized protocol.
Fortunately, we don't have to speculate, because decentralized social media already exists in the form of the "Fediverse"—a portmanteau of "federation" and "universe." Much like the decentralized infrastructure of the Internet, in which the HTTP communication protocol facilitates the retrieval and interaction of webpages that are stored on servers around the world, Fediverse protocols power "instances," which are comparable to social-media applications and services. The most important Fediverse protocol is ActivityPub, which powers the most popular Fediverse apps, notably the Twitter-like microblogging service Mastodon, which has over a million active users and continues to grow, especially in the wake of Elon Musk's purchase of Twitter.