When there are "too many" comments on a confluence page or blog, a link to "show all comments" is shown. It doesn't show all comments though. It seems to show the start of all threads and have links to "View the rest of this thread".

I guess if the initial link said "show all comment threads" (if that's genuinely what it does) I would find this less annoying.

Generally though I think a link to "show next N comments" at the end of the comments would suit me better. having to show all comments then show all the comments in each thread is a really irritating way to have to read them.