Re: Wiki vs Article?
1) I think wiki pages would be more appropriate. Articles, to me, are more in the mold of time-sensitive news reports, announcements, etc. The layout of wiki pages is less constrained and they have a revision history.
2) Yes, you can use categories to apply permissions for viewing pages. The permissions can also be set via wiki page structures and for individual pages. This amounts to "virtual wikis" in the sense that users can only see the pages they have the permission for, and not the others.
-- Gary
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