Unsubscribe and Purge
The unsubscribe and purge command addresses are slightly more sophisticated than the other commands.
As of Lyris version 3.0, the unsubscribe and purge addresses are customized for every recipient.
By default, Lyris 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 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 bounced from. This is a great advantage that Lyris has over other list
servers, as most list servers have great problems unsubscribing people when a message is forwarded to a new email address: they cannot determine what the original subscriber address was.
The "Y" at the end of "1234" is a "check character" that Lyris 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 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.