While many of them are moving to group chats and private Discord servers,tens of millions have moved to new social media platforms that advertise (though they don't necessarily deliver) decentralization: Mastodon (and the fediverse) and Bluesky (and the atmosphere).
Decentralization is itself a defensive countermeasure (code). When a service has diffuse power, it's harder for any one person to take it over.
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