Yes the Drupal equivalent of a wiki are 'book' pages or 'notes' as they're
called in OpenAtrium. A note can have a parent note, the list on the right
provides navigation. As far as i know it doesn't do concurrent editing and
easy creation of new pages like a true wiki. If you're used to mediawiki
it's probably a step back. I believe there is a mediawiki integration module
for Drupal but i don't know if it would work in openatrium.

Did the CND team create a list of requirements for a project management
site? True wiki pages for each project is a good one. I think Trac has
something like a true wiki but it seems to be more of an issue tracker for
developers.

That distinction is relevant by the way, there is project management
software and there are issue trackers. While there is a lot of overlap
between these two types they are not really the same thing. Although maybe
there is something in between that can serve both needs, but i havent seen
something like that yet.

/JG