[rnovak]

There are a lot of people on HN, and a lot of people with downvote privilege, and there are a lot of people who just generally downvote because they disagree with something.

Even if your opinion is completely positive, if people disagree, and a lot of people see it, you will get downvoted just because they disagree (and no one will reply to your comment to disagree, it's a drive-by-downvote).

There's also verification of this by HN mods: Several comment threads exist where they keep increasing the downvote threshold (from 300, to 400, to 500, and beyond). But it still doesn't solve the problem.

[runawaybottle]

Perhaps some random percentage of down-votes should require a response (every third, or something).

[veddox]

I find that really annoying when people downvote a comment because they don't agree with it. IMO, the downvoting privilege should be used only to indicate a flawed argumentation or negative content.