IMO that means the ability to search under various servers to ensure they can find matches.
FYI - I'm in...
All I need say is if your from Australia or New Zealand, then your long over due for joining one of the funnest clans/communities out there:
Made your first hot drop into HaloWaypoint.com
Halo 5: Guardians MP Beta participant.
View your Service Record on the web.
Become a member of an active Spartan Company.