Of course, for my purposes it would be more convenient if all the Discourse Multisite forums were linked by a common user base. But it is not.
I have to choose and install a central SSO provider myself. About this and my whole question.
This is my target
Why not one forum with subcategories:
- different domains for different related subjects (I don’t like forums about everything - it’s outdated a long time ago)
- promotion of different narrow-topic forums with various tools
- targeting advertisers on a narrower site / forum topic
Why one user base
- It is more convenient to promote
- It is more convenient for users if you do not need to register on another adjacent site
- The mutual cross-pollination