You can, but only briefly. HN gives you a short “oops window” to delete comments. Officially it’s for typos. Unofficially it’s a dignity rollback mechanism for people who realized mid-thread that they don’t actually understand what they’re talking about.

To be fair, i appreciate both types of deletions. If somebody feels they were just adding noise, Im very happy if they can reduce that noise.

I confess to using it under both circumstances at times.

Sometimes you think you know…

Same, I’ve made dumb comments and repented before. Better than not repenting.

Eh, even when I understand what I'm talking about, sometimes I submit a comment and then instantly realize "you know what, I actually don't want to debate this with a random stranger on the Internet".

I don't understand every comment as an invitation to debate. You can just not respond to people if you don't want to.

The point is that sometimes I only realize I don't want to after I hit the "reply" button!

People will never admit they don't know what they're talking about.

I don’t know what you’re talking about… ;)

You are allowed to delete your comments for a short time, as long as no comments are posted in response.

I'm not sure what happens with down votes on a deleted comment.

Downvotes on a comment have already affected your total karma score. Deleting the comment doesn't undo the karma loss. However, you have a chance to avoid further karma loss if you decide to delete the comment shortly after it starts getting negative reactions. (I have done this when I realized that my comment was getting downvoted for snark.)

I have deleted in the past, and saw my score immediately jump, but perhaps I was being upvoted elsewhere.

Or maybe it was the tooth fairy.

No idea.

I think this is one of the "worst" features of HN.

Ephemerality and forgetting are important for society and we need more of it.

I'd really like to see someone from the EU push for GDPR Right to Forget, or CCPA.

You can nuke your account by doing something completely egregious like challenging someone here to a duel (it's happened! - account and all post history deleted - we don't see the -deleted-- placeholder as much as we used to)