I could have sworn that there was a thread about this yesterday but I can't find it.
So, in order for Diplomacy to be recognised as a class of game, there needs to be a Standard set of rules.
In order to create this we need a collaboration of both Diplo players, Diplo makers and Staff, whether the last one will actually be fulfilled we will not know for a while.
In most diplomacies:
Declare Turn X, Attack Turn X+1. Alliance Sizes are 2 players to 1 quarter of the total people playing, excluding players who quit. Don't play slowly. PM allowed. Breaking rules results in becoming a PE.
In some diplomacies:
Surrenders must be accepted. PEs can agree to contracts to end their PEity sent by the victim.