Stopping Email Churn in its Tracks

Your email list is a living, breathing, evolving asset. It needs ongoing care and maintenance to remain healthy. How you manage it can make a significant difference in costs and results.

Writing off or deleting undeliverable emails has a bigger cost than you may realize. During a roundtable d3 hosted at the 2018 Catalog and Integrated Marketing Summit, we offered tips to reduce list churn and profitably re-engage subscribers.

What makes email undeliverable?

A healthy list contains validated, deliverable email addresses. A good email address can become undeliverable due to a variety of factors. Here are a few of the technical things that impact deliverability:

  • Defunct address — People change jobs, get married or finally cut the cord on a dated AOL address.
  • Bounce — Server rejects incoming mail for any reason.
  • Blacklisted — A domain or email has been placed on a naughty list and your ESP won’t deliver to it.
  • Mail box is full — No room for your message.
  • Blocked — Rather than take the time to unsubscribe, a recipient simply blocks your address.

Email subscribers are fickle, there’s no doubt. Beyond the technical reasons, subscriber interest levels impact deliverability and create churn, which is a percentage of how many subscribers leave your list in a given period. Churn is normal and to be expected. Recipients can easily lose interest if you haven’t emailed them in a while, or if your offers aren’t resonating with them.

They may also become turned off if you send too many offers in a brief time frame — a subjective perception that of course varies wildly from subscriber to subscriber. Some may take the time to unsubscribe, while others simply stop opening your emails. This is known as opaque churn.

In addition to opaque churn, there is transparent churn, which includes unsubscribes, hard bounces and spam complaints. These are addresses you cannot mail to anymore, due to their action (or inaction, in the case of hard bounces).

Just how much churn is to be expected? According to MediaPost, opaque churn rates are likely between 10% and 25% annually for most brands. Transparent churn can vary more widely, typically 25-50% annually.

Regardless of type, churn consumes 25-35% of the average email list every year. It’s a simple equation: your brand’s list growth efforts must outpace your churn rate. If they don’t, no matter how much list building you do, your list size will remain stagnant or start to shrink over time.

What can you do to reduce churn?

When it comes to unsubscribes and spam complaints, there’s nothing digitally you can do. Be sure to keep your unsub files up to date and suppress these records in email campaigns using third-party data. Otherwise, you run the risk of angering customers and violating CAN-SPAM. Consider reaching out to these customers via postal if their potential lifetime value merits the expense of a mailer.

For hard bounces, a thorough hygiene and append process can typically reclaim 20-60% of your file, depending on the age and quality of the data available. In this case, the undeliverable email address is matched to a third-party database, validated, appended and a reactivation message is deployed to the recipient on your behalf.

This process can occur at both the household and individual level. It’s fully compliant and a quick, easy and cost-effective way to recapture hard bounces. Depending on your file size, d3 recommends email appends 1-2 times a year (quarterly for very large files).


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To reduce opaque churn, your copy, offer and subject lines are the best place to start. Test, test, test subject lines; consider including an emoji or hashtag. Examine your preview copy with a critical eye — is it compelling enough?

Other things to try: using a different email platform or server; this may increase open rates. You can also switch channels — postal, phone or text if the addresses has opted in. If your house files are incomplete, they can be appended to allow for alternative or omnichannel engagement.

You can also reengage subscribers via CRM retargeting in email newsletters, programmatic campaigns and across your customers’ preferred social media channels. Lists can be loaded onto a variety of platforms to allow for targeted engagement where the customer is currently active.

Finally, don’t overlook the importance of regular list hygiene in ensuring a healthy list and maximum deliverability. From a data perspective, there are simple things your data partner can do to clean up your house file that pay big dividends:

  • Validate existing data as current
  • Append missing email addresses
  • Help revive older list assets you haven’t used in a while

If you haven’t spoken to a data partner, you should! This way you understand all the options available to you.

Commit to ongoing list building

With an expected amount of churn reaching 25-50% annually, every brand needs a dedicated, ongoing list building program. In addition to working to retain as much of your current email list as possible via hygiene, best practices and relevant messaging, you should have active programs underway to build new prospects. These may include efforts like lead gen, third-party email campaigns and social media outreach.

The most effective way to ensure your list is responsive and minimize churn? By making sure you’re distributing the right content with the right frequency. Make it a practice to test your campaigns with small list segments before deploying to your entire list.

So, the next time you’re tempted to simply purge your undeliverable emails and call it a day, try some of these tactics. You may be surprised at the number of subscribers you can save and restore — and the return generated by your next email campaign.