Quote Originally Posted by Brandish View Post
It comes down to the specious case of being able to do cross realm grouping, which as far as I know requires RealID.
If you want to do cross-realm grouping, you simply type /invite charactername-realmname (you don't need to be on anyone's friends list). If you use ISBoxer, it already does this for you assuming you've given it the proper character and realm names.