ircII help: load silent

Usage: LOAD silent
  A series of ON commands, which will make all of the *** join, leave,
  signoff nickname and mode change messages disappear. Meant to be used
  in high-traffic channels such as #report.

  If you have %U somewhere in your STATUS_FORMAT variable, the messages
  will appear in the status line instead, which is much less annoying,
  than to have them in the ircII windows.