Well, you know anyone can comment and surely can downvote him. If we need "to add something to discussion", let's have a moderation. Let a bunch of karam >= 500 to decide before publishing. Don't downvote. It's stupid.

There is a reason why upvote exists. It pushes good discussion top. If you are worrying about space complexity: good news! HN is using a modern database, not flat file. You can store 10k comments.

> There is a reason why upvote exists. It pushes good discussion top.

And downvoting helps push bad comments down, which is by design.

> If you are worrying about space complexity: good news! HN is using a modern database, not flat file. You can store 10k comments.

This is irrelevant to having a good discussion.