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.
Plus, if this becomes the "bot wild west" at such an early stage, the credibility hit will be a serious hindrance to future growth...