Why should we upvote or downvote a comment?
scscsc: You can't tell people how/when to upvote/downvote/do nothing.  It will not work and people will try to game the system.  People will vote based on instinct.For example I upvote what I like/agree with.  I downvote stupid or wrong stuff.That being said, I think the HN community has regulated itself remarkably well so that truth/content gets sufficient votes and falsehood/noise gets downvoted, and heavily so if needed.