We all have learned to love and hate the "report spam" button, an increasingly common feature in desktop and Web-based email programs. The idea is that, if a user receives a spam message, he or she can click this button and report back to the ISP or spam filter. This helps build a better view of what the user (and, in the case of ISPs, all users) thinks of each particular message.
It is a powerful system for several reasons.
First, it gives the ISPs direct feedback they can act on.
Second, it enables users to better train their ISPs and their own personal spam filters about what they like and don't like.
And third, in some cases, ISPs will let ESPs know when the button was clicked so that ESPs can remove users from the offending lists. This helps ESPs keep cleaner lists, and helps ensure recipients no longer receive communications they don't want.
Unfortunately, this approach has one huge hole: there is no second button.
Without an "unsubscribe" button, users have no choice but to click the spam button for messages they no longer want to receive, as well as for messages that truly are spam. And, because the spam button is the number-one reason senders get blocked at ISPs, the absence of this critical distinction can have big implications for senders' deliverability.
The good news is that help is on the way. A rapidly emerging standard quietly being adopted by ISPs everywhere can address the problem. It's basically a universal, standard unsubscribe mechanism. The technical specification is called ARF (Abuse Reporting Format), and it can be used for a wide variety of purposes including (and especially) to report unsubscribe requests.
My hope is that ISPs and email programs will begin widely adopting this option and provide unsubscribe buttons next to their spam buttons. Senders would probably have to qualify receive the unsubscribe feedback (some form of white-listing). But with it, they could cleanly remove recipients' email addresses from their lists without simultaneously experiencing a jump in their spam scores.
You can read more on the technical aspects of this emerging standard at the Mutual Internet Practices Association's Web site: http://www.mipassoc.org/arf/.