Leveraging an FBL to Reduce Complaints

Before I joined Return Path, I worked as the Postmaster at a North American cable provider/ISP. My memories from those years, specifically 2006 or so (my memory gets fuzzy as I get older) include attending conferences and participating in online discussions about what was then a new idea in the email industry, the Feedback Loop (FBL). I remember thinking how great it would be to have a mechanism in place for me to let senders know that my customers didn’t want their mail anymore, and I worked feverishly to put a home-grown system in place to make this happen, before eventually outsourcing its hosting to Return Path.

After the FBL’s launch, I then sat back and watched, and wondered how I could’ve been so wrong about FBLs. It seemed that, at least among the FBL enrollees that I talked with, complaints they got from the FBL either prompted fears of being blocked by me, or they were viewed as mistakes by the complainer; the complaints certainly were not seen as a reason to unsubscribe the complainer. I recall telling enrollees that complaints were an indication that my customer didn’t want that mail, and that the sender should do what was necessary to make sure my customer didn’t complain anymore. Perhaps I was at fault here, because I don’t recall that I ever explicitly said “Unsubscribe the complainer”; however, I couldn’t and can’t fathom why one might continue to send mail to someone who had explicitly said they didn’t want it.

Years on, FBLs are still in widespread usage, but I still don’t hear anyone talking about using them as de facto unsubscribe mechanisms, and I’d like to revisit this idea. I think that during the holiday season, when the frequency of mailing increases and senders mail to a wider audience than during the rest of the year, it is especially important that you make sure you’re not annoying your recipients (or their mailbox providers).  I’ll present here arguments I’ve heard against using complaints in this manner and try to refute them, but I’d love to get your thoughts in the comments.

Mailbox Providers Redact the Email Address, So I Can’t Tell Who Complained!

I think this claim is nonsense (and my previous employer was one that required redaction).  Between Variable Envelope Return Paths (VERPs – http://en.wikipedia.org/wiki/Variable_envelope_return_path), X- headers, and URLs in the message body, it is quite possible for senders to insert identifying information about the email recipient into the message that will come back to you as part of the complaint.  So long as that information is not the email address itself (or anything that looks like the email address) you should have all the information you need to remove the complainer from your lists.

Complaints Only Happen to Bad Senders. I’m Not a Bad Sender, So These Complaints Are Mistakes!

There’s an incident from a conference years ago that still sticks in my craw. There was an open discussion session taking place, one where smaller groups were convened around easels with large notepads, and the topic of discussion was related to FBLs and complaints, and I remember someone wrote this on one of the notepads:


The word was in quotes, and the implication was that complaints were essentially mistakes on the part of the person who clicked on “This is Spam”, I guess because only bad mailers would generate complaints, and everyone at the conference was a good guy. In my experience, it’s the opposite that is true.

There are three kinds of email that get sent to mailbox providers on a daily basis:

  • There’s the stuff that gets rejected outright, due the sender having a poor reputation
  • There’s the stuff that gets accepted and routed to the Spam folder, due to either the sender or the content having  a poor reputation, and
  • There’s the stuff that gets accepted and routed to the Inbox

I have yet to see a mail system that provides an active “This is Spam” button for mail in the Spam folder (because the mailbox provider already knows that it’s Spam), and it’s literally impossible to click that button for mail that was never accepted.  So, if we accept that the Inbox is the province of the good sender (or at least the sender who hasn’t yet proven himself bad) then it stands to reason that only good senders will receive complaints about their mail, because users can only complain about mail that is in their Inbox. If you want to continue to be a good sender, you’ll make sure that this person doesn’t have any further opportunities to complain about your mail.

There’s No Way That Recipient Meant to Mark Our Mail as Spam. This Complaint Is a Mistake!

This is a closely-related variant of the above, and indeed it’s possible for someone to mistakenly click “This is Spam” on a given message, but so what? You’re keeping track of the complaints you’ve received, and so you’re able to deal with the fallout of this mistake.  If the person stops receiving your mail and notices, they’ll either re-subscribe or complain to you or their mailbox provider.  If they re-subscribe, you’ll have a special confirmation process set up for such people, letting them know that they previously complained about your mail and so you stopped sending them mail; if they do it again, they’ll never be able to subscribe to your mailings. In the same manner, if they complain to you or their mailbox provider, you’ll both have evidence to show the person that the mail stopped because they said they didn’t want it anymore.

This Is Just Encouraging List Washing!

This one comes more from the anti-spam zealots than from the actual FBL enrollees (not to say that FBL enrollees aren’t anti-spam, mind you), and it’s one that I really don’t get. It may in fact be an argument against providing an FBL, but that’s a lost argument; FBLs aren’t going away, and so enrollees must make the best practical use of the complaints they receive. As it is impractical for a sender or the mailbox provider to directly engage each person who complained to find out why the person complained, the best practical use of complaints, in my opinion, is to remove the complainer from your subscription lists. There’s no point in continuing to send mail to someone who’s marking your mail as Spam, because that person is clearly indicating that your mail is unwanted.


Those who know me may have heard me say from time to time that senders should “Send mail to people who want it, but only send those people mail that they want.” FBL complaints are a great way to find out who doesn’t want your mail, and you should use them as a way to remove from your lists people who don’t want your mail.

If you've got something to say about this post, either comment below or contact me at [email protected]

Thanks for reading.

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