[Linosaurus]

Centralized moderation is a big thing.

Usenet was a very open system, where iirc moderation sometimes happened per discussion group but otherwise everyone individually had to ignore bad actors (add to killfile). It scaled badly with more people and spammers. Arguably it started going downhill 30 years ago. Found a decade old discussion:

https://news.ycombinator.com/item?id=9987679