Unsubscribe and Purge
The unsubscribe and purge command addresses are slightly more sophisticated than the other commands.
As of Lyris List Manager version 3.0, the unsubscribe and purge addresses are customized for every recipient.
By default, Lyris List Manager uses the mail merge tag $subst('Email.Unsub') in the default footer defined for a new mailing list. This mail merge tag gets rewritten for each recipient, so that they
see an unsubscribe address customized for them.
For example, if a member belongs to a list called "jazztalk" and happens to be member #1234, their unsubscribe address might look like this: unsubscribe-jazztalk-1234Y@clio.lyris.net
The -1234Y portion of the unsubscribe address uniquely identifies the recipient, so that when they send email to it, Lyris List Manager will know exactly who is unsubscribing, no matter what email
address they sent the unsubscribe request from.
This feature is known as "failsafe unsubscribing" because it always works no matter what email address the original message was sent from. This is a great advantage that Lyris List Manager has over
other list managers, as most list managers have great problems unsubscribing people when they have changed their email address or a message is forwarded to a new email address: they cannot determine
what their original subscriber address was.
The "Y" at the end of "1234" is a "check character" that Lyris List Manager inserts, to ensure that the "1234" number was typed correctly. This prevents people from accidentally mistyping their
unsubscribe address, and thus unsubscribing the wrong person. For example, if someone mis-typed their address as "unsubscribe-jazztalk-12344Y@clio.lyris.net" (by adding an extra 4), Lyris List
Manager will detect that the number is not typed correctly, and ignore the "12344" number, instead unsubscribing the person who wrote the message, as determined by the From: line.