Or maybe into some usenet-news format...
I know some mailing lists are "converting" emails into forum posts and offer a nntp(?) view too. So people who like newsreaders can do their thing, and people who prefer email can do their thing, and people who want to use forums can do their things as well.
What I am trying to say: while there might not be an export/view of the forum to treepadlite .hjt, there might be one for "something". I would assume it depends on the features of SMF (greatest forum software I have seen so far).