[KajMagnus]

You can also have a tree view side-by-side with a flat view — see this comment (in this discussion): https://news.ycombinator.com/item?id=48770861

If you click a comment in the flat view, the tree view jumps to that comment, so you can see it in its context.

> You can have a chronologically sorted tree view

Couldn't that be a change-sort-order-button? But this doesn't solve the find-the-most-recent-comments problem?

[krapp]

I have a browser plugin that highlights most recent unread comments on HN with a yellow background, and counts new comments in the thread listings. One could even add "next unread" links as well.

I've seen imageboards that toggle between a flat and tree view with javascript.

Any feature you can think of has probably been implemented by someone at some point. Unfortunately almost no one cares about forums anymore so trying to innovate in the space is a waste of time. Only a very fringe subset of nerds (myself included, I still weep for my HN clone in Hack that will never be finished, and my Godot client that will never be released) considers forum UI design to be interesting.

[KajMagnus]

> no one cares about forums anymore so trying to innovate in the space is a waste of time

Not sure about that. To me it looks as if Facebook is self sabotaging, for example their local events page is broken and has been for years. FB-the-company seems defunct internally, and if they start fading away (slowly over many 10s of years), maybe forums will make a comeback (slowly). Also, if AIs destroy Reddit, this might be an opportunity for smaller forums that have ways to block boring AIs.

> Any feature you can think of has probably been implemented by someone at some point

Definitely not :- )