Credits Renée DiResta is an associate research professor at the McCourt School of Public Policy at Georgetown.

For the past two decades, most online discourse has occurred on a handful of social media platforms. Their dominion seemed unshakeable. The question wasn’t when a challenger to Twitter or Facebook might arrive but if one could ever do so successfully. Could a killer new app, or perhaps the cudgel of antitrust, make a difference?

Today, those same platforms still enjoy the largest user bases; massive breakout successes like TikTok are the rare exception, not the rule. However, user exodus to smaller platforms has become increasingly common — especially from X, the once-undisputed home of The Discourse. X refugees have scattered and settled again and again: to Gab and Truth Social, to Mastodon and Bluesky. 

What ultimately splintered social media wasn’t a killer app or the Federal Trade Commission — it was content moderation. Partisan users clashed with “referees” tasked with defining and enforcing rules like no hate speech, or making calls about how to handle Covid-19 content. Principles like “freedom of speech, not freedom of reach” — which proposed that “borderline” content (posts that fell into grey areas around hate speech, for example) remain visible but unamplified — attempted to articulate a middle ground. However, even nuanced efforts were reframed as unreasonable suppression by ideologues who recognized the power of dominating online discourse. Efforts to moderate became flashpoints, fueling a feedback loop where online norms fed offline polarization — and vice versa.

And so, in successive waves, users departed for alternatives: platforms where the referees were lax (Truth Social), nearly nonexistent (Telegram) or self-appointed (Mastodon). Much of this fracturing occurred along political lines. Today the Great Decentralization is accelerating, with newspapers of record, Luke Skywalker and others as the latest high-profile refugees to lead fres