I think this is simple and reasonable, and it's usually the particular pain point I usually mention while grinding away on my "downvotes are bad" axe. I think this is better than tags because the universe of possible reasons to downvote something appear to be so large that we'd need a large menu of flags to select from, and also would need to be able to select multiple flags, making scoring posts (which I still think is useful) very hard.

It would be interesting, too, if the downvotes could, themselves, be downvoted by others, rendering them valueless. That is, if my explanation for my initial downvote doesn't pass muster, others could downvote-the-downvote, and the initial comment (which I had downvoted) would be left with its full complement of points, as though I hadn't downvoted it to begin with.

There's already a mechanism for this. It's called upvoting.

An upvote is semantically different than a downvote. A downvote is like saying "I am providing negative feedback", while a downvote-downvote is like saying "You have no reason to provide negative feedback".

An upvote on the otherhand is "I'm providing positive feedback".

It would be good if "cancelled" downvotes were deleted or hidden. I think there is a risk of downvote explanations cluttering things.

This seems like a cool idea, just not sure how it could be implemented. Any examples of something like this you know of?

Closest example I can think of is Amazon's "did you find this review useful" button. You can suss out — somewhat — how helpful a review is.

That would only be fair because the downvote to your downvote comment would also have to provide a reason. So, it would encourage a real discussion.

I upvoted this because I think this is reasonable. The purpose of HN is to be a discussion forum, not a karma generating tool. Requiring comments for votes (particularly downvotes) fits the theme.

After following this topic for a while, it seems that the main problem is objection to comment-less downmods, not downmods in principle.

Precisely.

As this thread and numerous others are demonstrating, there is a group of people that lurk and troll through the consequence-free mechanism of the downvote. I don't really care who the top downvoters are (though the metrics would be interesting, I'd like to see different mixes and matches of the various statistics that HN could generate, upvoters, downvoters, karma, number of posts, average comment scores etc), but I think there should be some limit per unit time they can downvote. Like say 5/every 30 days or some such. Given how many perfectly reasonable comments in this topic have been downvoted, I would suspect it's the same lurker-trolls every time, they would have just blown their quota for the month under this kind of system.

And if you notice, it's like pulling teeth from an angry lion to even get any of these guys to bother posting a reason. The answers so far seem to amount to either

1) My time is too important, I'm too important.

2) The downvote is enough reason, it should be obvious to the recipient that they weren't contributing anything.

I'm sorry, but I don't find either of those reasons even remotely satisfying.

I don't think you're right. The reasons seem to be that people are downmodding as a social normalization function. It's like saying "don't post more like that please".

I think you are taking downmods a bit too personally.

Well, different people are having different takes on the semantics I guess. How about a quota though? Nobody likes an overly negative person at a party. IRL, we can't enforce good behavior that way, but here we can through the power of software.

I don't think a quota makes sense. But a comment/vote does.

I don't want to limit the amount of times a person can disagree with me (at risk of allowing for disagreeable persons).

I think this sounds interesting, but with this system, it becomes more critical for the crows to know the rules.

However, a lot of that might be solved by using words instead of arrows. E.g. a "Agree", "Disagree" and "Detracts From Conversation" button.