Fediverse

Heavy moderation. Some real people will be flagged as bots, but it's the only way. A well-prepared prompt can be indistinguishable from human language. Registration questions will only block bots because they stop bot makers from registering thousands of accounts at once.

Servers with lax signup requirements will need to be blocked (temporarily?) when spammers find their way in. Detecting links and other promoted content can easily get rid of the commercial spammers, but it gets harder when you're trying to block political bot farms. Even still, Fediverse software lacks any kind of standard "firewall" against spam, as a few Japanese teenagers demonstrated with a script not that long ago, and the trolls spamming child porn before them.

On the wider Fediverse, it's quite possible to set up a Lemmy server consisting entirely of bots, or a whole network of them, first only interacting with each other but soon becoming part of the wider Fediverse.

Luckily, almost nobody cares about the Fediverse and the few bad actors I've seen don't care enough to actually put in any effort. If the Fediverse does ever grow to become a sizable influence on the internet, we're pretty much fucked.