Code:

on *:JOIN:*:.timer 1 1 maxjoin $chan
alias maxjoin {
  echo -a JOIN $1 $nick($1,0,a) $($+(%,chanmax.,$1),2)
  if ($nick($1,0) < $($+(%,chanmax.,$1),2)) { return }
  set $+(%,chanmax.,$1) $v1
  ;;;; Your actions below this line ;;;;
  msg $1 New high count: $v1
}

on *:TEXT:!maxusers:*:{
  if ($($+(%,chanmax.,$chan),2) !isnum 1-) return
  ;;;; Your actions below this line ;;;;
  msg $chan Current high count: $v1
}



Currently, the code keeps track of any channel that the bot/script is run on.

-genius_at_work