Set/unset channel operator. Requires that
you are channel operator or channel founder.
+ b <nickname>[@<server>]
+
+ Set/unset channel message blocking. Client
+ may set this mode only to itself. When set
+ the server will not send channel message to
+ to the client. This mode can be used to block
+ unwanted messages if desired.
+
+
See also: CMODE, UMODE