I see one big problem based on my experience: on an open and generic network (like facebook) there are huge masses of ignorant/mislead/biased people as well as a lot of trolls (people abusing the system for the sake of abuse).
When any kind of scoring system is based on the size of the population these people may input significant amount of bogus results.
Building a web-of-trust may work but same problem exists: ignorance-wot would be huge.

The Fediverse enjoyed (and partly still does) a rather homogenously educated and open community but it's observable that lot of unreliably trustable people have joined and they keep joining. Community moderation this way may shift from reliable to unreliable, unless new people are following he local habits of taking care. [If there's such a thing here.]

@grin interesting. That makes sense. Any system that can be gamed will be, especially if there are incentives to do so. There are ways, programmatic and otherwise, to make gaming moderation systems more difficult or ever impossible. You’re right: so will try to poison data in a users-moderate set up. One vital piece will be filtering that poison data out. Not easy and also not impossible.