I was going to suggest that a link to the Discoure help be included from the forum. However, having looked around there only seems to be http://learndiscourse.org/ 
I came across the ‘Dismiss’ button and wondered what it actually did. I realised that I would need to know this forum was built on Discourse to find that information which I only know as I followed this from the start. This then led me to realise there is no footer indicating what the forum is built on which is a good way of promoting open source software as well as helping in finding info about how to use it.
To me the weakness of Discourse is the user help. You seem to simply need to try it and find out what happens. Yes some of it is intuative but, for instance, what is the difference between a new post, an unread post and a latest post (they all order slightly differently)? Just one example of not really being sure how to use it.