> it's frustrating both to have one's own comments downvoted without explanation, and to come across a comment that's grey without obvious reason (Was it factually incorrect? Endorsing an unpopular idea? It's not always obvious).
Personally, I don't downvote anything unless it's either complete and utter bullshit (e.g. someone acting like PHP is bad based on arguments barely valid in the end of the PHP5 era), or it is plain and simple far-right/conspiratorial in nature. It used to be the case that this was how most people used the downvote feature.
Nowadays? Seems like the tide has shifted, and even completely legitimate viewpoints (not just on politics threads) get downvotes for unexplainable reasons. It saddens me a bit.
> I'm not saying HN should do exactly the same thing, but one example is Slashdot's system where a comment can get downvoted in a way that tags it specifically as trolling/offtopic/whatever
Such a thing exists. You have to open the comment's dedicated page by clicking on the timestamp; if you're over 500-1k karma you can then flag it. Enough flags auto-kill comments and they only appear for those who have "showdead" enabled.