The basic problem is two very incompatible goals. You don't want to become part of an echo chamber[1], but at the same time you want to protect yourself from fools. The hope of every moderation system is to solve both. We've seen HN-style crowd control and folks on twitter using ban lists, and both have problems.

In a lot of ways, I think Advogato[2] was on to something with their web of trust. The line on wikipedia Despite the trust metric, posting privileges to the front page of Advogato have been gained by controversial individuals, leading some to claim Advogato's trust metric solution is faulty. seems like sour grapes. I still think its worthy of another couple of steps down that path.

Also, I think folks miss handling the joy of tangents cause a lot of problems in moderation that are really just a structure problem. Mostly they are marked as off-topic and down-voted which cuts down on some amazing streams of knowledge. I have yet to see a system that allows branching of something the poster knows will be off-topic but is a tangent of the main article. It seems like generated articles might be the way to go and leave a "tangent pointer" in the main article. I think solving the tangent problem would solve a lot of moderation problems and hard feelings of the users.

I really don't like some solutions, like shadow banning or making every comment by a user drop to the bottom of the sort right away with little hope of getting "above the fold" no matter how many upvotes the comment gets.

1) Although, quite a few people actually do want to be part of the majority with only the "acceptable" opposition represented. This pattern repeats so often, it makes me think its just baked into humanity's tribal thinking.

2) https://en.wikipedia.org/wiki/Advogato