The Discourse Blog seems to be built with Discourse, but it doesn’t look like a forum - notably, there are “Notable Replies” below certain posts and the layout is much different - what tools were used to build the blog?
I think it is WordPress. You can include discourse as comments provider for any blogging system.
I do know that - but the Discourse Blog does not include any iframes in the Responses section, nor does it make any XHR requests - so I guess that’s not what it’s using
It’s WordPress and probably using the wp-discourse plugin.
Maybe Discourse API
They have their own customized WordPress theme