How to Define Active Email Marketing Audiences as Opens Depreciate [on-demand webinar]

November 19, 2021 | 8 minute read
Chad S. White
Head of Research, Oracle Digital Experience Agency
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Apple’s Mail Privacy Protection (MPP) will likely only be the first mailbox provider to flood marketers’ systems with fake opens, obscuring real ones. Welcome to the Age of Email Open Depreciation. Although far from perfect, opens were email marketing professionals’ most frequent signal of engagement, generally clocking in at about eight times the number of clicks. As such, marketers relied on the metric to drive a range of activities. For example, you can use email opens to define active subscribers for targeting and inactive subscribers for suppression.

While email clicks can fill the void left by opens when it comes to send time optimization and subject line optimization, email audience selection requires a much broader approach. Going forward, the best way for you to define a subscriber as active or inactive will entail looking at both their activities as a subscriber and their activities as a customer across other channels.

To do that successfully will require brands to look at the right customer activities and use appropriate lookback windows for both existing subscribers and new ones. We provide an overview of these issues, including some helpful visuals, in this on-demand webinar. We discuss each of those issues in more detail below.

Building a New Email Marketing Audience Filter

In the Age of Email Open Depreciation, marketers need to use a combination of email behaviors and cross-channel behaviors to build active subscriber audiences. Let’s look at what could be included in each of those behavioral buckets.

Email Behavior

Engagement with your email campaigns is still the strongest indicator of an active subscriber. When defining an active subscriber, start by using:

1. Real email opens

Despite what some misleading headlines claim, opens aren’t going away entirely because of Mail Privacy Protection. That’s because Apple’s privacy changes won’t affect all of your subscribers. Even if the majority of your subscribers are impacted, digital marketing platforms like Oracle Responsys can remove the misleading auto-generated opens created by MPP, leaving you with only real opens that you can reliably use for audience selection.

Be mindful of the systems in your email marketing stack that can’t filter out auto opens generated by Apple, says Clea Moore, Director of Strategy for Email Deliverability Services at Oracle Digital Experience Agency. “It’s important to consider this when building an audience because you could inadvertently pull in cached auto opens from the Apple Mail app with your safe, real open data,” she says. “That could muddy the waters, causing you to send mail to inactive subscribers.”

However, even if your brand has a relatively small audience of Apple Mail app users, you’ll have a sizable subscriber engagement gap that you’ll need to fill by looking at other metrics beyond real opens.

2. Email clicks

The email channel’s second-most-frequent engagement signal, clicks will become undeniably more watched and more heavily weighted when making decisions. That said, there is a danger that MPP will cause marketers to over-optimize their emails to drive clicks because they want the engagement signal, not because it creates the best subscriber experience.

Remember that MPP doesn’t change the open rate performance of your emails; it only changes your visibility into your open rate performance. However, if you redesign your campaigns to move valuable content from your emails to your landing pages, you’ll have reduced the value of opening your email for your subscribers. On top of that, you will have added significant friction to the interaction by requiring subscribers to visit your landing page to get value out of the interaction. Over time that might discourage subscribers from opening your emails, resulting in fewer engaged subscribers when your goal was to increase engagement.

Cross-Channel Behavior

Wise marketers have always considered behavior outside of the email channel when selecting audiences. For instance, you could have a chronically inactive subscriber who is an active and valuable customer. Your messages may influence their behavior in ways that aren’t directly traceable back to the emails, so the smart bet would be to continue emailing that subscriber. Marketers will now need to take similar calculated risks more broadly in their audience building. For subscribers where you don’t have real email opens or clicks, consider factoring in:

1. Web sessions

Many subscribers will visit your website directly via a browser after having read your email’s envelope content. Others will open your email with images blocked. Still others will open your email with MPP enabled. In each of those instances, you got a web visit because of the email, but not a click. So, it’s reasonable to email subscribers who have visited your website recently, even if you’re not seeing open or click activity from them. If they log into their online account, that’s an even stronger indication of engagement.

2. App sessions

Similar to web sessions, your email could be the trigger that led a subscriber to be active on your mobile app.

3. SMS and MMS activity

“While the clicks from these channels would ultimately be reflected in web or app sessions (unless they come through as anonymous), the click activity would be clear and telling,” says Clint Kaiser, Head of Analytic & Strategic Services for Oracle Digital Experience Agency. “That’s especially the case if you’re orchestrating SMS with select email messages.”

4. Call center activity

Depending on your industry and the products and services you offer, many of your customers may feel more comfortable reaching out to your customer service reps by phone to get answers to their questions. Sometimes your emails prompt those questions, indicating email engagement.

5. Purchases

"Purchases are another way to identify active subscribers who may be influenced by your emails even though they don’t appear to be opening or clicking," says Heather Goff, Strategic Director of Email Deliverability Services at Oracle Digital Experience Agency.

“Working with our clients, we score audience segments based on two factors, potential financial benefit and risk to deliverability,” she says. “Looking at past purchases is one way to help inform which segments are safe, although it’s important to recognize that not all purchase sources are equal. For example, while third-party purchases perform as well as first-party purchases, online purchases are stronger signals than offline purchases.”

Setting up auto-pay is evidence of a customer’s deeper engagement with the brand overall, and Heather says that could also justify inclusion in email audiences.

Cross-channel behaviors aren’t an ideal proxy for email engagement, but they’re the best way to compensate for the loss of real opens caused by Mail Privacy Protection.

Lookback Windows for Email Marketing Audience Selection

For each of the factors above that you use, you’ll need to establish an appropriate lookback window—that is, the period of time during which you’ll consider that activity useful in building an active email audience segment.

To compensate for the loss of opens, we’re already seeing some of our clients experimenting with longer lookback windows of up to 24 months for email clicks. Time will tell if that wide of a window jeopardizes their deliverability.

“The critical thing to keep in mind is that all data points are not equal,” says Daniel Deneweth, Head of Email Deliverability Services at Oracle Digital Experience Agency. “Real email opens and clicks, because they come from the email channel, are going to have the biggest impact. It’s not uncommon for brands to mail subscribers who have opened an email in the past 12 or even 18 months. However, activities from outside of the email channel will naturally have a weaker correlation to email engagement, and therefore a much shorter lookback window should be used for these activities. Determining the most appropriate lookback windows for each activity will require some exploration and testing.”

In general, the higher the email frequency of a brand, the shorter the lookback window that they can use for email and cross-channel engagement. And if you don’t see any activity from a subscriber over a long period of time, then you should move them to your suppression list.

New Subscriber Rules

Of course, these lookback windows don’t apply to your new subscribers who haven’t engaged. For these never-actives, you’ll need an entirely different set of rules.

With new subscribers for whom you’re not seeing auto opens, it remains the best practice to suppress them if you don’t see activity after your first five to seven emails. That protects your brand from sending to spam traps that can get your emails blocklisted. Suppressing inactive new subscribers will also prevent wasted efforts, as well as offer some protection from accidental signups and malicious signups by people other than the address owner. Typically, subscribers are the most engaged in the weeks after they sign up, so it’s a major red flag when a new subscriber isn’t engaging.

However, for new subscribers for whom you’re only seeing auto opens, you’re going to need to adapt your approach. The safest and most straightforward approach is to ask for a click, says Daniel.

“Clicks remain the strongest positive signal we have for qualifying a new subscriber as safe to mail, which is why they’re the heart of double opt-in (DOI) confirmation,” he says. “If you’re not running DOI, ask for a click throughout your welcome series. Provide compelling reasons for them to click, whether it’s redeeming a welcome offer, selecting preferences, or answering a progressive profiling question that will provide immediate value to the subscriber.”

Getting that first click also rules out the possibility that a new address belongs to a spam trap. While the largest and most impactful spam trap operator, Spamhaus, has said that they won’t use Apple’s Mail Privacy Protection to obscure the behavior of their spam traps, smaller operators have made no such pledge. So, while the absence of real opens is still a potential red flag that you’re mailing a spam trap, now only seeing auto opens is also a worrisome sign.

Building a new audience selection process for email marketing takes time. You’ll need access to omnichannel data, and you’ll need to test to determine the appropriate lookback windows for each data point. Don’t allow Apple’s auto-generated opens to cause you to bloat your active mailing list with subscribers you’d have never included before, as that will most certainly lead to deliverability problems. And don’t wait until you experience blocking and junking to start reworking your audience selection criteria. At that point, the remedy will be extra costly.  


Need help with your digital marketing campaigns? Oracle Digital Experience Agency has hundreds of marketing and communication experts ready to help Oracle customers create stronger connections with their customers, partners, and employees, even if they’re not using an Oracle platform as the foundation of that experience. Our award-winning specialists can handle everything from creative and strategy to content planning and project management. For example, our full-service email marketing clients generate 24% higher open rates, 30% higher click rates, and 9% lower unsubscribe rates than Oracle Responsys customers who aren’t.

For help overcoming your challenges or seizing your opportunities, talk to your Oracle account manager, visit us online, or email us at

Want to better understand your email marketing risks and opportunities, take advantage of our free Email Marketing Assessment. Our experts will check your deliverability, review your email creative, audit your signup process, do a partial competitive analysis, and more. If interested in this free assessment, reach out to us at

Chad S. White

Head of Research, Oracle Digital Experience Agency

Chad S. White is the Head of Research at Oracle Digital Experience Agency and the author of four editions of Email Marketing Rules and nearly 4,000 posts about digital and email marketing. A former journalist, he’s been featured in more than 100 publications, including The New York Times, The Wall Street Journal, and Advertising Age. Chad was named the ANA's 2018 Email Marketer Thought Leader of the Year. Follow him on LinkedIn, Twitter, and Mastodon.

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