I would like to have a single sign-on solution made for multiple XF installations. I am not sure how easy or hard that will be from a developer viewpoint, though it would need atleast: Ability to initially sync from all boards and infer some type of manual / automatic overwrite method for same users across multiple existing forums. I would imagine this would require two addon's, one for the master, then another addon installed into all slaves. Ability to sign-in from any board URL (so multiple sync to all slaves after registration) No interference for user permissions (being they remain on a per installation basis) I'm sure there are more points... and/or suggestions from others. Basically, I want to be able to sign-in on any forum, and once signed in, I can use the other forums with the same user login details. Not sure how the register would work... whether all sites are redirected to the master site for registration, then redirected back to the referring site on completion... obviously must factor in email confirmation and such. I want to be able to control each forum uniquely though for usergroup and user permissions. Can it be done and how much? Also, I would like the developer to support the mod here freely for everyone to use.