Andrew Bernard writes:
Under Users for a list, there is a category for List nonmembers. What does this term mean? [It's rather curious philosophically when you think about it, because I would have thought that the category [all humans - list members] fits that category term.]
I don't recall the exact definition of "list member", but I can't resist explaining the "philosophy". :-)
In the mail system as a whole, what we can confirm is a mailable mailbox. That corresponds to an *address* in Mailman. But users (typically humans) often have multiple addresses, that they would like to configure together (eg, single signon, same setting for not-me-too, etc). Thus we have a *user* concept, which requires a agent to log in and establish a *user* and attach addresses to it. I don't remember the exact details, but both *users* and *addresses* can exist independently of the other, though they are normally linked. Finally, a *subscription* is a link between an *address* and a *mailing list*.
ISTR that merging *users* in the database is kind of annoying, so instead of automatically creating a *user* to back every known *address* (eg, when banned or moderated), the *address* is allowed to participate in the list as a banned or moderated address without being related to a *user*. There may be other cases where an *address* lacks a *user*.
I'm pretty sure there are ways in Postorius to create a *user* that has no *addresses*, although I've not tried, and I don't know if such Postorius users would be reflected in the core database.
Steve