USER MODE w

Usage: UMODE +|-w
Usage: MODE <nick> +|-w
w - Wallops
Messages sent by opers to users will be visible. This is usually a good mode to have set on. Opers will sometimes send information that is helpful but not urgent through wallops. For example, if the network were in the process of rerouting some servers, causing some quick splits, there might be a wallop about it.
Privilege: user
Examples:
/mode jimmers +w
/umode +w

USER MODE W

Usage: UMODE +|-W
Usage: MODE <nick> +|-W
W - Watch list exception for +m
This mode is only effective if you have UMODE +m set, it allows users to message you if you have them on your WATCH list.
By using +m and +W, you can declare which users may message you, just by adding the nicks to your WATCH list. This can be useful if you are busy or just want to talk to a very few, possibly only one user at some point.
Privilege: user
Examples:
/mode jimmers +W
/umode +W
See also: UMODE +B