(Deprecated, except for peered lists; included for backwards compatibility)
Defines the list password. When sending the list back to the server, the password is prefixed to the list file for validation (see the Validate= command for more specifics). The PW= parameter is "invisible" once it is defined; that is, for security reasons, it does not appear either when the list is reviewed or when it is retrieved with a GET command by the list owner.
LISTSERV auto-generates a 16-character random password for lists at list creation time if this keyword is not explicitly defined, making such lists more secure from random hackers. Both LISTSERV maintainers and list owners are now encouraged to use personal passwords (defined with the PW ADD command) in preference to list passwords for this reason.
The one exception to this keyword's obsolescence is when you are creating peered lists. Peers must have the same PW= setting, so you cannot use the LISTSERV-generated random password when creating peers.