Stephen Downes

This looks like a nice service: "Fediponics scores every new signup, catches bots before they post, and shares threat signals across instances. Keep your community safe without spending hours reviewing signups by hand." I haven't tried it, since I don't run an instance, but it comes well recommended. "The scanning and scoring engine behind Fediponics is published as Fediponics Core. Self-host it free on a single instance, read the code that scores your signups, or send a pull request — the hosted product on this page is built on that same core." There was a GitHub but it seems to be gone now (not a good sign).