I wasn't particularly clear, apologies. I was really referring to instances where navigating the tree view was a core part of the interface.

This means being able to expand and collapse the tree easily, as well as identify quickly nodes that have replies.

On a typical Usenet reader, new replies are normally highlighted, and read nodes/subthreads can be quickly collapsed, often by default.

Neither of those are possible with HN, Reddit or typical NodeBB sites where every post is displayed whether read or not.

Or the even more niche 'Reddit'.