This depends on the List-Unsubscribe header: http://www.list-unsubscribe.com/ http://www.list-unsubscribe.com/ which can be set to an email address or link. If

This depends on the List-Unsubscribe header: http://www.list-unsubscribe.com/ http://www.list-unsubscribe.com/ which can be set to an email address or link. If you're adding remove links to your outgoing emails, you might as well put it in the header as well. Hotmail/live mail will only show the link for trusted emails IIRC. As Gmail has no "feedback loop" that sends spam reports back to the sender, this is better for me (as an email sender) than nothing. People regularly report email as spam that they signed up for and that they just don't care to receive anymore (they even report transactional email as spam, such as an ordery summary/order shipped email).