Resolution: Won't Fix
NOTE: This suggestion is for Confluence Server. Using Confluence Cloud? See the corresponding suggestion.
This could be similar to this document for JIRA
It would include things like:
- Why you would want to federate and why problems it solves.
- How many spaces you might want per site
- How to break up your Confluence site into multiple sites
- What Federation features are available to you.
It could even be part of the Operating+Large+or+Mission-Critical+Confluence+Installations guide.