This is activated whenever someone on a channel you are on leaves irc. Normally, the display would show: *** Signoff: <nickname> but, of course, you can change this. If <nick> is your own nickname, then the action will be taken when you exit from irc. The parameters are as follows: $0 The channel from which the person signed off $1 Nickname of person who left irc $2- Text of Signoff message.