I want to have a wordpress installation as main site, and xenforo as forum.mainsite.com. As far as I know, Google sees subdomains as different sites from the main site, more than a subfolders.
I was just thinking. I want the wordpress posts to automatically publish to threads in a specific forum (via the excellent feed importer). Will Google see this as dubplicate content? Preferably both the blog posts and the discussion threads should be searchable via google.