> It encourages and prominently displays good quality comments, and discourages and buries poor quality comments. It's not a perfect system as a lot of people vote based on whether they happen to agree rather than based on a comment's quality, but it's much better than nothing.

Mostly. There is an unconscious hive mind on HN too, and it downvotes when you disagree with it. It just happens that most commenters belong to it, at least most of the time.

The same effect would be achieved without showing the numbers though. That's where the addiction comes in.

I don't see the numbers on HN? Which is why it is less addictive to me than Reddit. I also lurked for nearly 2 years, as I was concerned about diluting conversations with low quality, unnecessary posts, which are far less frequent on HN than Reddit.

edit: Now I see the numbers. The quality of posts is still far better than Reddit and the interactions less addictive, at least in my experience.

There's still value in knowing the scores though. When it works, it encourages better conversation, and this effect might be weakened if you couldn't see your comments' scores.

Slashdot's approach is to have different kinds of upvote (Insightful, Funny, etc) and different kinds of downvote (Off-topic, Flamebait, etc), and scores are clamped, iirc the lowest value is -1 and the highest is +5.

https://slashdot.org/faq/mod-metamod.shtml