i still feel the hn engine is optimised for expounding rather than discussion. the threading is nice, but in the absence of a reply notification, and with the nesting depth capped, having an actual discussion tends to be difficult.
It's true. There's no use replying to a comment that's a few days old, because I won't expect even the commenter to page that far back on their comments page, so likely nobody will even read it (given that it's far enough down the page).