>I've often wondered what a forum would look like where you could make the equivalent of 'aside' comments. The way someone might, while you're speaking, say softly "hyPERbolee, not HYper-bowl" to correct you without interrupting.

That would either be PMs, or the forum equivalent of posting "sage" on an imageboard (which prevents the post from bumping,) neither of which HN supports.

Although given the forum's focus on quality over quantity, I think some kind of "whisper" mode might be worth looking at, to opt out of having such comments from appear on the new comments page.