The current problem I'm having with Wirebird is deciding how to present
resources so that they're convenient for both machines (standalone
clients or advanced JavaScript on our own pages) and humans browsing
the site.

The main resource structure looks like this:

Categories,
which are a collection of groups.

Groups (=mailing lists, =blogs),
which are a collection of topics.

Topics, which are a collection of
pages (posts, replies, and eventually wiki pages).

The problem is
rather visible on the wirebird.com pages right now... to get to any
content, you go to the main page, then you go to a category, then a
group (where you get to see a little content, in the form of the
most-recent-post preview in each topic), then the topic where you get a
list of threads, and then, finally, you can click on a thread and hey,
there's finally some actual *content*.

This part is a little better...
main page, category, and the group has the content since topics are a
little downplayed in blog style.

And if you look at the Phoenyx forum:
http://forum.phoenyx.net/, you see a more webforumish setup, but that's
the less-RESTful version of Wirebird. It also starts to break down as
you get more and more content - the Phoenyx is small enough to get by
with all the *topics* on the main page (especially since all the groups
are single-topic), but that will get overwhelming with a large site.
And that's important: for the machine side, we don't want to have
clients that assume there are going to be (for instance) topic- or
thread-level pieces in the category or group resources, and have that
go away when the site gets larger.