Slashdot does this.

What generally happens is that instead of one argument about been downvoted/upvoted you end up with even more arguments about whether something is +5 funny or whatever.

I've no idea how you solve this in the general case tbh.

Part of that though is that +1 Funny doesn't add to your slashdot karma. So people sometimes "upvote to denigrate" because you can only get +5 anyway, a silly comment can get +5 Funny without actually rewarding the commenter (mocks the comment) - you can see this when replies get +5 Insightful or +5 Informative and are very contrary to the original comment.

Personally, I like the idea of having qualifiers on the downvote without one on the upvote - makes you think a little bit before downvoting... plus the vote buttons are ridiculously small on an mobile Safari - so having to click twice would prevent accidental downvotes.

So far, while it may not be ideal, I think HN actually hits pretty close to the sweet spot.

thanks i'll check it out. I wasn't thinking to show the stats to others, possibly to provide feedback to the poster that they're 'above average' on the 'mean' or 'not relevant', etc scale.

I havent put a lot of thought into an ideal solution to this problem. But heres the best I have so far. Change the definition of karma to capture notability which would be a monotonically increasing number. So when a person mark a comment as notable, it increases your karma score by 1. Seperately have a agree / disagree score per comment whose lifetime is limited to a particular thread. Within a thread a reader can use the agree / disagree scores of comment to selectively read both sides of the debate.

I don't have a strong opinion on whether that'd work, but it sounds a lot like the Slashdot comment moderation system. Perhaps someone with a good level of experience of posting on Slashdot can help shed some light on how it works out in practice.

I think it works well (been reading and posting to /. for about 15 years), and if I designed a forum then it'd work the same way. The trick is it forces you to justify your opinion in some way. There isn't a "-1 Disagree" or "+1 Right On" so to mod a comment you have to find some actual flaw with it, or justify why you think it should be raised above the rest. If you pick a dumb reason that clearly can't be justified based on the text, meta-moderators will wash things out later.

That said, it's not perfect. There are -1 Overrated and +1 Underrated mods. I would not have these if I was king for a day, because:

• They apparently somehow bypass meta-moderation, or have done in the past (!) so not surprisingly they get abused a lot

• They are vague and don't force you to justify what's good or bad about a post, in many cases I have seen abuse of these mod types devolve into reddit style agree/disagree modding

• They don't adjust the adjective that goes with the post, so for a long time and maybe still now you can get posts like +5 Troll or -1 Insightful, which is just confusing and generally bogus

Stripping out Underrated and Overrated would improve things a lot. I'd maybe make +1 Funny count for karma too because funny posts deliver a lot of value to the slashdot reading experience, IMO, and I see no problem with encouraging them.

I think the balance of adjectives is important though. There is no -1 Wrong or -1 Misinformed mod and that's important. If someone posts something polite, earnest and completely wrong there's no justifiable word to mod them down with. Instead you have to wait for a reply to correct them and then mod that up as Informative, Insightful etc.

Another idea is to make down voting cost karma. Stackoverflow does this.