If I may bring up German again, where the use of the dual system of second person pronouns is alive and well: the inferior/superior distinction ("du" and "Sie", respectively) aptly sums up how it works. However, some of the fine points of the game are rather interesting. My favorite example: when hikers reach a certain altitude (I've forgotten how high, but pretty high up), everyone is permitted, even expected to address each other with the familiar "du" form of address!