For example, the whole "If my friend deletes his journal, can I get another code?" Yes, an FAQ states that codes aren't re-usable, but it is under the title "How many invitation codes can I generate?," which is not somewhere I would look for that information if I needed it. The explanation of why codes are in place is "hidden" in "How do I create an account?." It is helpful there, for those who don't yet have an account, but I don't think it's an intuitive place for already existing users to find it.
Do others think that a general explanation FAQ on invitation codes might be useful? (Perhaps under a less poorly worded version of: "How does the invitation code system work? Why is it needed?") What other pieces of information would you want to see included in such a FAQ?
Edit (16:01): I do know how to edit posts to communities, emmavescence. *grin*