• By late 2023–2024, major centralized platforms like Facebook/Instagram, X (Twitter), YouTube and others became subject to the EU’s Digital Services Act (DSA), which imposes strict content-related obligations: removal of illegal content, mitigation of systemic risks to civic discourse and public security, transparency on algorithms, and the threat of fines up to 6% of global revenue for non‑compliance. These rules first applied to designated Very Large Online Platforms (VLOPs) from August 2023 and to essentially all platforms from February 17, 2024, with enforcement by the European Commission and national regulators. (commission.europa.eu) This matches Friedberg’s “regulatory hammer” scenario of governments telling platforms what they can and cannot make available.

• After the October 2021 episode date, several Twitter/Facebook‑like decentralized alternatives either emerged or significantly matured:

• Bluesky / AT Protocol – A decentralized social network and protocol originally incubated inside Twitter; the AT Protocol spec was first released in 2022, the Bluesky app hit app stores in 2023, and the network opened to the general public in February 2024. It offers a feed-based experience very similar to X/Twitter and is explicitly designed as a distributed social protocol. (en.wikipedia.org)
• Farcaster / Warpcast – Farcaster is a decentralized social protocol (founded 2020) whose main client, Warpcast, launched in February 2023. Warpcast offers short posts (~320 characters), follows, likes, and reposts—directly comparable to Twitter/X or Facebook’s feed—while user identities and data live on a shared decentralized protocol rather than a single company’s servers. (theblock.co)
• Nostr – An open, censorship‑resistant decentralized social protocol using public‑key identities and independent “relays” instead of a central platform, explicitly designed to avoid any single entity deciding who can speak or what can be said. It gained notable traction by 2023, with tens of millions of registered users across its ecosystem. (en.wikipedia.org)
• Mastodon (Fediverse) – While Mastodon predates the prediction (launched 2016), it is a decentralized, federated microblogging platform that closely mimics Twitter/X and has seen renewed surges in adoption as an alternative social graph. (en.wikipedia.org)

• These systems all provide similar discovery and access use cases (feeds, follows, discovery algorithms, public posting) to Facebook/Twitter‑style platforms, but operate on decentralized protocols or federated architectures where control is spread among many servers or protocol participants rather than a single intermediary.

• We cannot cleanly prove that regulation alone caused their emergence—other forces like ownership changes at Twitter/X and broader interest in Web3 also mattered. But Friedberg’s qualitative prediction was that heavy regulatory pressure on centralized platforms would be accompanied by the emergence of alternative, more decentralized platforms serving similar social‑discovery functions. That is exactly what happened in the 2022–2025 period.

Given that (1) strong content/speech regulations have in fact been imposed on major centralized platforms, and (2) multiple decentralized alternatives with comparable social‑discovery roles have emerged or significantly grown since the prediction, the forecast is best judged as right in its main thrust, even if the causal chain is not perfectly isolatable.