Regarding discussions, this is a bug. I have logged it here: http://www.jivesoftware.com/issues/browse/FORUMS-3135
There has been some debate about whether to include moderated threads for an internal release, if you can setup a space that moderates it''s threads, you need to be able approve/reject them.
Regarding documents however worked fine for me. I setup a user (test3) as a space approver. I then logged in as user test1, and created a document. Instead of the publish button, I got a "Submit for Approval" button. After submitting, I logged back in a test3, and under "Your stuff" in the top nav bar, I had a "Document Awaiting Approval"