I'm writing from Italy and I'm new to WordPress, so please excuse me if this question is trivial, I searched through these forums but I was not able to find anything useful to me for this issue.
I'm setting up a blog where all registered users should be able to create posts (i.e. Authors role), and to add new categories, but I would not like them to be able to remove existing categories (maybe created by other users), only Administrators should to this.
I also installed "Role Scoper" plugin to see if it matches my needs, but it seems it can't, maybe I'm wrong.
How can I achieve this goal? Is it possible to use an existing plugin or do I have to write a custom one? Or do I have to hack WordPress code itself? If so, may you please me point at the right part?
Many many thanks for your kind reply,