From the NannyMUD documentation

LAST CHANGE

2000-12-18

COMMAND

NAME
        echo - echo a message to everyone in the environment


SYNTAX
	echo 

DESCRIPTION
	The string is sent to all players in the same environment as yourself.
	This should be used with great care, and NOT to confuse others or to
	pretend that someone did things he/she/it didn't.


NOTE
	People have been demoted for abusing this.