Email Inactivity Is Woefully Underaddressed

Four years ago, when I started laying the groundwork for the recently released Email Engagement & Deliverability Study, whether subscribers engaged with your emails was considerably less important. Now that ISPs are increasingly using engagement metrics to determine deliverability, it’s vital to maintaining healthy inbox placement, especially for high-volume senders.

In that light, I was shocked to find that so many major retailers continue to mail chronically inactive subscribers. For the study, we subscribed to the email programs of over 100 major retailers using fictional personas. We opened and clicked on the emails we received until one day we stopped -- and let 40 months pass. At the end of that more than 3-year period, we found that…

31% Continued mailing, no frequency reduction

23% Continued mailing at reduced frequency



14% Stopped mailing, no frequency reduction

32% Stopped mailing after reducing frequency

According to Return Path research, only 81% of all permissioned email worldwide makes it to the inbox, with the remainder either routed to junk or undelivered. Poor list hygiene and management of inactivity levels are big contributors to the reduced deliverability, which translates directly into lost revenue.

The more we examined retailers’ behavior, the more it became clear that the vast majority didn’t have a rigorous program in place to address inactivity. Here are the three steps that we advise:

1. Define an “inactive subscriber.” It’s important to separate this definition from any existing definitions of “inactive customers.” I’ve seen several cases where retailers have confused these two definitions, to the detriment of their email program.

Subscriber inactivity should be defined by behavior in the inbox, which is all that ISPs care about when deciding whether to deliver email to a user. They don’t have visibility into whether that user is a loyal customer of yours or not, and don’t care. Purchase behavior can be tricky since shoppers often don’t act in a straightforward manner, so for the purposes of email engagement, keep a tight focus on email -- not business -- metrics.

While each ISP has its own thresholds for inactivity, we’ve found that in general any subscriber activity within 1.5 to 2 years is acceptable. But we certainly recommend testing to determine where the line of engagement is for your own list.

2. Create a reengagement strategy that uses changes in email frequency and content to keep subscribers from becoming inactive. Reducing frequency to inactives or those headed toward meeting your definition of inactive is a key tactic for minimizing the risks that these subscribers pose. We found that 55% of retailers eventually reduced the number of emails they sent to inactives, with frequency reduced by 69% on average.

Reengaging subscribers with content changes proved to be more challenging for retailers, with only 16% of them trying to reactivate lapsed subscribers with different offers, subject lines, formats or other content changes.

3. Establish rules for removing inactives. Eventually marketers need to accept that the risks of mailing long-term inactives significantly outweigh the potential for revenue from them. While I’ve heard some folks circulating the ridiculous advice to drop inactives after 6 months without a click or open, we’ve found that a reasonable tipping point is around the two-year mark. Of the 46% of retailers that stopped mailing actives within our 40-month window, the average duration of inactivity before a subscriber was dropped was 28 months, which isn’t too far outside of our recommendation.

Just as triggered reengagement emails were rare, so were triggered re-permission emails that gave inactive subscribers one last chance to indicate their interest in continuing to receive emails. Of those retailers that stopped mailing inactives, only 16% of those sent a re-permission campaign -- and we suspect that some of those weren’t triggered campaigns, but batch campaigns that were sent in response to a block at an ISP. Developing a triggered program around reengagement and re-permission can help avoid blocks, junk foldering and the need to take sudden and drastic action to get back in an ISP’s good graces.

Defining email inactivity and developing a program to address it takes a fair amount of testing to determine the right levels and triggers for an individual brand, but it’s well worth the effort. Engagement metrics are only likely to be become more important to deliverability going forward.

1 comment about "Email Inactivity Is Woefully Underaddressed".
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  1. Rita from FreshAddress, Inc., December 6, 2011 at 9:39 p.m.

    “While each ISP has its own thresholds for inactivity, we’ve found that in general any subscriber activity within 1.5 to 2 years is acceptable.”

    It is possible that the recipient changed their email address and/or is not reading the one you are mailing. Perhaps two years is too long to lose track of their interest to competitors as there is a 30+% attrition rate annually on an email address. “While each ISP has its own thresholds for inactivity, we’ve found that in general any subscriber activity within 1.5 to 2 years is acceptable.”

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