Please. Captcha by default. Email domain filters. Auto-block federation from servers that don't respect. By default. Urgent.
And yes, to refute some comments, this publication is being upvoted by bots. A single computer was needed, not "thousands of dollars" spent.
The admin https://lemmy.dbzer0.com/u/db0 from the lemmy.dbzer0.com instance possibly made a solution that uses a chain of trust system between instances to whitelist each other and build larger whitelists to contain the spam/bot problem. Instead of constantly blacklisting. For admins and mods maybe take a look at their blog post explaining it in more detail. https://dbzer0.com/blog/overseer-a-fediverse-chain-of-trust/
Who controls the Overseer Control?
It's been answered further below. Yeah it's that one bloke who did it at https://lemmy.dbzer0.com/u/db0 . The projects also open source though, so anyone can run their own Overseer Control server, with their own chain of trust whitelist. I suspect many whitelists will pop up as the fediverse evolves.