If you saw a warning message telling you to read this, beware! If anyone on irc told you that typing "on ^MSG * $1-" or "on ^MSG <nick> $1-" would speed speed things up or otherwise make life better for you, they are lying. The above commands allow people to send you msgs and have them executed as commands by your IRCII. This can be a major security problem, since the person who told you to do this can then execute any command you could, including exec commands. This would give them control over your account while you are on irc.
Anyway, if you did see this warning, it could be that someone is trying to abuse your account. But, don't worry, the exec command that it warned you about was not executed. If you are unsure about what is going on, please contact your local irc operator for help. If you know what you're doing, you can set EXEC_PROTECTION to OFF and exec will be allowed within on commands. Only do this if you are sure you understand what is going on.
See Also: exec