Unless you use https://www.hnreplies.com/, you don't get a notification for when someone has replied to your comment. Even then it is as an email, decreasing immediacy and causing back and forth sessions to have overhead.

I understand this as an intentional feature of HN.

thanks, I hadn't known about this service!

Me too. :-)

I used to be able to jump into a big discussion, read dozens of comments, log out, and the next day could go back and read the NEW comments in that discussion. With HN, I can do that for my own comments, but otherwise, I have to jump back into the whole thread and scroll past all the accumulated discussion to find new contributions.

And good newsreaders were also able to selectively skip a comment and everybody replying to it (e.g. if a discussion devolved into a tangent that was less interesting), instead of a whole subject.