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.
Everyone is talking about how these things won't work. And they're right, they won't work 100% of the time.
However, they work 80-90% of the time and help keep the numbers under control. Most importantly, they're available now. This keeps Lemmy from being a known easy target. It gives us some time to come up with a better solution.
This will take some time to sort out. Take care of the low hanging fruit first.