Improving E-mail Deliverability with E-mail Feedback Loops


by David Addison

An e-mail feedback loop (FBL) is a service whereby a mail provider (such as Yahoo! or AOL) will notify senders of complaints. Early-on these were called junk mail responder (JMR) services. They're free and an industry best practice. On the mail-provider side, FLBs are beneficial because they help to proactively reduce spam sent to their users. Feedback loops are one of the ways to report spam. Providing a FBL is a choice of the mail provider. Subscribing to and using FBL data is a must for e-mail service providers (ESPs) and large private bulk mail senders like Dirigo.

For years, end users have been told not to trust the e-mail unsubscribe links. They’ve been taught to flag e-mail as spam in Outlook or to simply hit the spam button in webmail as an alternative to unsubscribing. Reporting spam may act as unsubscribe if an e-mail sender is properly using FBL technology. How to respond to FBLs is voluntary for both the sender and receiver. The Internet Engineering Taskforce (IEFT) created the RFC 6650 which sets the standards for the creation and use of e-mail feedback reports. While the system is far from perfect, it is all that we have until Messaging Malware Mobile or Mᵌ or MAAWG finalizes the FBL 2.0 initiative. The new protocol is said to be a win-win-win for senders, users, and mail providers.

Dirigo sends as many as 20 million e-mails a month from proprietary e-mail sending systems that we’ve built over the years. This is a proprietary system comprised of software and hardware that we host from the Dirigo Portland Maine datacenter. Sending bulk e-mail and triggered e-mail is a service that we perform for our larger clients. In the 5MM+ e-mail bracket we’re less expensive and more efficient than top ESPs. Our delivery rates are superb too! We’re 100% white-hat shop—we only send permission-based e-mail. We get to the inbox, in part, because we use FBL systems. We used our first FBL system in 2004 after returning from the Inbox E-mail Event confrence in 2004. Since then, they’ve become a part of our e-mail process. Subscribing to and reporting on feedback loops is a requirement for any e-mail marketer.

It sounds easy, right? But it’s not! You adhere to white-hat practices... yet your emails are being blocked and your sending domain is close to being blacklisted. In this situation toxic e-mail addresses (people who are chronic complainers) play an important role.  Sending one wrong e-mail can land any brand into e-mail purgatory or jail. Testing tools like Email Reach and Return Path's Email Certification Program (formerly Sender Score Certified and before that -- Iron Port's Certified Sender) help, but, they cannot cleanse a dirty list.  They're just reporting tools.  The trick to keeping your reputation hight (e.g. Cisco's IronPort or Return Path's is to act on FBLs and bounces.

Here’s how Feedback Loops work. Bulk senders (e.g. Dirigo clients) register to join feedback loop programs (or we register on behalf of our clients). There are lots of small but important requirements for acceptance into FBL programs—mostly, adhering to e-mail sending best practices (SPF, domain keys, opt-in best practices, clear opt-out link, clean IP addresses, etc.). Meeting the base requirements is often easily achievable, except for AOL that requires double opt-in.  Double opt-in is a big issue for negative option marketers. Once accepted into a program the mail provider will forward complaints originating from their users to a dedicated e-mail address of your choosing (e.g. End users are encouraged to report e-mail abuse from their e-mail interface (web mail clients). Hotmail customers click a “Junk” button to report spam. Yahoo! e-mail users click a spam button. When a user clicks on a spam button because an e-mail is unwanted, the mailbox provider will send a copy of the e-mail back to the complaint-forwarding address of the sender. In many cases the e-mail provider will expunge the e-mail addresses from the returned e-mail so that they abide by their privacy policy.

So, what good is a returned e-mail if you don’t know to whom it was sent? Senders using feedback loop techniques inject x-headers into the header of the e-mail. X-headers are fields in the request HTTP header. These fields are a non-standard or proprietary add-on to the regular fields in the e-mail header. X-headers can be used in many applications. Bulk senders using feedback loops insert an encrypt e-mail address or an ID number associated with the recipients e-mail address into an X-header. Mailbox providers return X-headers because they purport to have no way of knowing that they contain personally-identifiable information. A dirty industry secret is that e-mail providers know that X-headers contain personally-identifiable information and return them anyway (thwarting their own privacy policies). Shhh, don’t tell.

The rest is fairly simple. The offending e-mail gets forwarded to an e-mail box. Then we act on these e-mails. Dirigo uses a software application to process FBLs. Every five minutes the software picks-up the mail and parses the from line that identifies the mail as originating from a feedback loop system and the X-header. This data is written to a database table. A SQL service then opts out users from our mailing lists based on rules. We know who to opt-out because we look-up the value of the X-header that corresponds to an e-mail address. A single FBL complaint from a user triggers an unsubscribe.

What about bounced e-mails? We use a similar process for bounced e-mail. There are lots of different bounce types, we’ll not discuss them here. In a nutshell, we unsubscribe hard bounces on the first bounce and most other bounce types (e.g. soft bounces) at three bounces. This keeps our client’s e-mail lists squeaky clean.  The same software that handles FBLs also handles bounces.

In May 2012 we sent a quarter of a million e-mail address to the Fresh Address SafeToSend™ Service (Dirigo has a contract with Fresh Address for cleansing e-mail, address appending, reverse appending, etc.). This service utilizes a patented technology and vast knowledgebase to ensure that e-mail addresses are deliverable and worry-free. Our list came back from Fresh Address with little change because we actively process bounce and FBLs.  The exercises was a great test and ended up providing other value.  If you are actively acting on bounces AND FBL complaints AND sending valuable e-mail AND testing your e-mails against content filters AND have an active/recent list, you'll not have issues getting to the inbox.

A goodhousekeeping seal of approval. All of our larger senders of bulk e-mail subscribe to Return Path Certification. A bunch of ISPs both big and small have spam filtering systems that treat certified IP addresses differently than non-certified IP addresses (e.g. Comcast, Hotmail, Yahoo!).  Certification also loosens the flow rate and sometimes sidesteps aggressive filtering.  ISPs like Return Path Certified Mail because certification correlates highly to clean senders. Bad actors cannot get certified. The service is not cheap! Dirigo tests show that Return Path certified mail has an okay ROI.  The Return Path daily e-mail reporting is a good way to validate that you're properly acting on FBLs and bounce data.  Without such measures most senders would pierce spam complaint thresholds.

A mistake eager new e-mail marketers make in their quest to expand their subscriber base is being afraid to discard e-mail addresses. Another mistake is too aggressively tossing e-mail addresses to stay under the tiered pricing of ESPs (we cringe every time we hear about this practice). Common mistakes: not using bounce management to purge bad e-mail addresses, ignoring opt-in rules, not segmenting old portions of the list, and failing to use feedback loops. Don’t be a bad digital marketer! E-mail marketing is all about list quality and targeted marketing.

Constant Contact reports FBLs as spam complaints. All of the major ESPs (Cheetahmail, AWebber, Silverpop, ExactTarget, Experian, Epsilon, Lyris and Responsys) use FBLs because it is one of the best ways to keep a list clean.  It also keeps their shared IP addresses clean. If more than 2% of your list reports you as spam, you’re in big trouble.

Connect with Dirigo Design & Development and Connect with E-Marketing at Its Best

Deploying feedback loops and getting e-mail to the inboxes of your customers and prospects is a determined task that requires skill and vigilance. As an experienced Internet marketing organization, Dirigo deploys best practices like those noted above, plus myriad others, to create an environment for optimal inbox placement. We’re adept at building custom in-house and hosted e-mail delivery solutions for larger senders or those that require custom driven triggered streams of e-mail. Most of our outbound e-mail is relayed directly from dedicated client servers using proprietary Dirigo methods.

To discuss the ways we can help your organization maximize its inbox placement, as well as its online potential, call David Addison at 207-358-2980. We specialize in abandoned cart e-mails, trigger e-mails, reactivation e-mails, list cleansing, CRM integration, reverse appending, spam trap/honey pot problems, e-mail response management systems and more. We're here to help you connect with your customers and grow your organization.

Links to the most popular feedback loops:
(hint: if you have limited resources join MSN and Yahoo first)

AOL Feedback Look

Comcast Feedback Loop

Excite / Bluetie Feedback Loop Program

MSN, Live & Hotmail Junk E-mail Reporting Program (JMRPP)

NetZero & Juno (United Online) Trusted List Feedback Loop Request Form

RoadRunner Feedback Loop Program

Yahoo! Complaint Feedback Loop Program

Earthlink Feedback Loop
By e-mail:


Rackspace Feeback Lops

Principal Author: David Addison
Date of Publication: 06/14/2012
Last Modified: 12/22/2012


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