The shortest telegraph sent so far sounded quite smart and assertive... the Spartans were sons of war; born tough and rough. Once while a rival conqueror was in his mad pursuit, a messenger was sent to the Spartan King to scare them to their bones and weaken their spirit in a telegraphic language that read, "If we march into the boundaries of Sparta, your wives will become widows, your children will be orphaned and your land brought to dust." Now, the Spartans were not just brawn alone they had the brain to go with it. Soon the rival conqueror saw his messenger bring back a reply from the Spartan King and to his surprize found the same telegraph he had sent earlier brought back to him with the word "If" duly underlined.
Thus the shortest reply in history which read more than what was said. If only we learn to speak less!