It has been said that :-
Mornington Crescent has NO rules. It is not a game.
This is not the case. It is true that the rules of Mornington Crescent are not written down, and it is also true that the object of the game is not to reach Mornington Crescent. However, the rules of a game do not wholly determine how it is actually played: could you become a good player of chess or football merely from an inspection of the rules?
Mornington Crescent is a collaborative game. Moves are judged according to the context in which they are made and a good move in one game may be considered lame in another.
Mornington Crescent is not a game that you can win or lose, it is a game that you can have fun playing. Part of the fun is in introducing new players to the game: that does not necessarily involve systematic ridicule.
Mornington Crescent is not unlike Everything2.