If you're looking for a setting where you can enter a specific message to watch for, possibly wildcarded, at the moment, the only way of doing that is with a script. mIRC will monitor specific events, or places where events take place (and a "message" usually falls under the TEXT event). I did notice that there isn't an Event entry for Text or Action, and I suspect that this is due to the fact that the Text event would be triggered on any message sent.
