List Unsubscribe is a supplemental functionality that supplies a quick unsubscribe option for your contact via the email header. This functionality is not a substitute method for the unsubscribe link present in your message.
To enable List Unsubscribe, have your account's admin contact Higher Logic.
Why use List Unsubscribe?
As a sender you want to make sure you're sending your customers the appropriate type and amount of emails by allowing them to unsubscribe from content that doesn't interest them. They'll be more attentive to the messages which they do want, and will have a better opinion of your company, which means fewer complaints. This is also a matter of your sender reputation, excessive sending volume can cause internet service providers to filter out your messages and decrease your overall deliverability. Avoid this by making it simple for contacts to opt out of content they no longer wish to receive.