It'd be interesting to have a look at that news site forum (if you have a link?).

> messages are folding individually (i.e. only content is hidden but not the children)

Seems like a nice way to give a concise overview of the discussion (who replies to who, how long each thread is). I think it'd be nice to see the first rows of each message, so one knows what it is about (maybe one has forgotten).

> only new messages are shown in an unfolded state

(So that one directly sees the messages one hasn't read before, and can start reading them effortlessly, right)

> only new messages are shown

I wonder how they determine which messages are new. Maybe it's [new since one's last visit]? Or messages one hasn't read yet? Not that easy to know which messages the visitor has read, if many messages are visible on the screen at the same time :- )