Thank you for your input! The access control question is a good one, it
hasn't been discussed yet, but I will keep that in mind.
So as I understand it, Namespaces are quite useless (or not very practical)
in a wiki related to the wiki content, they should be used only for
structural things not relating to the content of the wiki (like Discussion
pages, Special pages, Special pages for extensions, etc.)
The project I'm thinking of would be a cooperation of two (or more) cities.
They could have their own pages in the wiki regarding their own topics. But
cities from the same region share the same regional laws and therefore can
cooperatate in putting knowledge in the wiki that is of common interest for
Consider a page type "procedures" with descriptions on how to carry out
public services as manual for public servants [[Category:Procedure]] with
the attribute [[scope::CityA]] or [[scope::Region]]. This sounds quite
straightforward to me.
But I also could define the pages being of a different type:
I think the choice between the two depends mostly on the question, whether
or not the page types share the same structure (attributes, templates, etc.)
which would lead to the first approach or if the pages have to be
independent from each other (which would be easier in the second approach).