This command will send a message to all users that are set mode +w.
Example:
/wallops We're going to be doing some re-routing, so you will experience some quick splits. Please be patient.
Wallops can be seen by anyone on the network, so they should be carefully considered before being sent. They are usually reserved for important information that would interest the users, but is not vital enough to be sent as a newsflash or one of the other methods of notifying most or all users.