Email List Hygiene

7 Email List Hygiene Tips for a Post MPP World

minute read

Post Image

Since its release in September 2021, Apple’s Mail Privacy Protection (MPP) has completely changed the email landscape.

Validity data shows that pixel fires associated with the Apple proxy skyrocketed to approximately 70 percent of total device usage by last December.

Unsurprisingly, MPP has had a broad range of effects on email marketers. One key challenge, and one we hear frequently from our clients, is the way MPP impacts email list hygiene.  

A clean list is the cornerstone of any successful email marketing program. But the notorious MPP has made go-to list hygiene practices less relevant.

Open rates are now less reliable, leaving senders feeling like they’re flying blind. If senders can’t use open rates to determine when a subscriber becomes disengaged, they run the risk of lower engagement rates, increased spam trap hits, and overall degradation of data hygiene.

A recap of Apple’s MPP

Need a quick MPP recap?

The new privacy standard prevents senders from using tracking pixels to measure open rates and device usage. It also masks recipients’ IP addresses to prevent location tracking.  

MPP accomplishes this by prefetching and caching email images at the time emails are delivered (as long as the device is connected to the internet).  

This means all tracking pixels will fire, regardless of whether the recipient actually opens the message. As a result, open rates skyrocket, but not because more people are truly engaged. 

The bottom line? Senders can no longer trust open rates. 

MPP’s impact on email list hygiene 

In the past, many senders simply used last open date (the date of the most recent email open for any marketing email) to determine whether a subscriber was active or inactive.

Now that open rate data is less valuable, it’s tempting to swap open rates with another metric to measure audience engagement, like last clicked date or website visits. While these data points are valuable, this ‘find and replace’ strategy may prove to be short sighted.  

Why? As consumer privacy concerns intensify, tech giants will continue to crack down on data collection. 

For example, Google plans to block third-party cookies on Chrome in 2023, leaving marketers to grapple with the loss of data points like subscriber shopping interests and frequently visited websites.  

This depreciation of traditional data points like these points to one solution: move forward.  

Senders must take a proactive approach to list hygiene and ditch the reactive strategies they’ve used in the past.  

Let’s take a look at seven ways email marketers can adapt and maintain clean lists in a post-MPP world. 

1. Use double opt in (DOI) 

List hygiene starts from the moment a subscriber opts into your program. One of the best ways to ensure data quality and high subscriber engagement is by implementing a double opt-in registration method.

Subscribers typically receive a confirmation email after they subscribe to your email program. Using a double opt-in (DOI) method, subscribers must click a link in the confirmation email before they’re officially added to your active list.

Many marketers avoid this strategy, fearing their acquisition efforts and list growth will plummet if they use DOI. But the benefits are vast.  

Research shows 80 percent of subscribers will confirm their email addresses in a DOI model. And quality over quantity is the central tenet of email list hygiene.  

Email programs that use DOI typically see higher engagement rates, and lower unsubscribe and spam complaint rates. Furthermore, they’re much better prepared for the myriad of privacy legislation we’ve seen enacted over the last decade (with more to come).  

In addition to these list quality perks, double opt-in prevents a major email list hygiene issue: spam traps.

Because spam traps are real addresses that can receive email, MPP can make these bad names appear engaged. Requiring confirmation after signup and reconfirming subscribers who haven’t clicked lately is an excellent way to maintain a clean list. 

2. Incorporate zero-party data

Because first-party data (inferred from online behavioral metrics like open rates) is becoming less accurate, marketers should focus on gathering zero-party data to improve message relevancy.

Zero party data is information customers knowingly and willingly share with your brand. 

It’s trustworthy, unique to your organization, and presents major opportunities to create privacy-first personalization.  

Some examples of zero-party data include personal context like a customer’s age, location, purchase interests, and communication preferences.  

Subscribers are generally willing to provide this information. In fact, 83 percent of consumers say they are willing to share their data to create a more personalized brand experience.  

Zero-party data is crucial to maintaining data quality because it primes subscribers to engage. It’s also free, compliant with privacy legislation, and accurate.  

To encourage your subscribers to share, be transparent about why you’re collecting certain information and only collect data that’s relevant to your business.  

3. Promote your preference center

Married to zero-party data is the email preference center.

Since MPP makes it more difficult to determine when disengagement happens, brands must rely on subscribers to actively tell them when they no longer want emails. 

A preference center allows customers to specify the content that interests them and indicate how often they’d like to receive it.  

As a result, brands with a robust preference center can send more tailored email communications, which increases their odds of positive engagement.  

While many email programs have preference centers, few actively promote them. 

Why? Marketers usually worry that promoting their preference centers will result in a wave of unsubscribes.  

It’s true that encouraging audiences to update their preferences may result in some opt outs. But providing this option helps prevent subscriber fatigue and leads to fewer reputation-damaging spam complaints down the line.  

To turn your preference center into a secret, list-cleaning weapon, let subscribers know it exists!  

Include links to your preference center in every email. And try sending dedicated emails that prompt subscribers to update their preferences.

4. Make unsubscribing simple

Many marketers believe unsubscribes to be a negative metric. But from a reputation standpoint, unsubscribes are far preferable to 
receiving spam complaints.  

Since MPP obscures genuine subscriber activity, making unsubscribe links prominent and simplifying the opt-out process are both essential to maintaining email list hygiene.

It’s possible that MPP’s automatic loading of images means more scrolling to find the unsubscribe link, which is usually located in the email footer.  

In response, senders should consider adding an unsubscribe link to the top of every email template.  

Be sure to leverage the List-Unsubscribe header, which allows subscribers to see an unsubscribe button next to the “From Address” when viewing your emails. This header adds yet another opportunity for easy opt out. 

Note: You can always include a ‘Change your Email Address’ option too! 

5. Establish a re-engagement series

Best-in-class email programs have a well-timed re-engagement strategy in place.

Since 22.5 percent of subscribers become inactive each year, re-engagement campaigns play an important role in winning back dormant subscribers or determining when to stop sending them email.  

Proactively asking your audience if they’re still interested in hearing from you matters even more post-MPP, since your subscribers’ engagement levels are now less certain.

If subscribers fail to engage with your win-back attempts, it’s time to remove them from regular mailings. Generally speaking, a subscriber can be considered inactive if they fail to engage with your emails for more than six months.  

Of course, this window will vary depending on your program. For example, if your brand only sends one email per month, your definition of inactive will differ from companies that send weekly emails.  

However you define inactivity, MPP can help senders gain valuable deliverability insights for re-engagement campaigns. If you see emails to inactive subscribers marked as opened, this confirms a) the address is still valid and b) your message reached the inbox.  

6. Revisit your recency algorithms 

Post-MPP, Apple Mail addresses will almost always generate a pixel fire. So, these users will give the impression of being active and engaged—even when they aren’t.

 It’s hard to rely on any one metric to determine if a subscriber has become disengaged. But layering multiple metrics can help senders rebuild their recency algorithms and move away from reliance on open rates.  

Instead of using click data alone, senders should consider building a hierarchy to determine subscriber engagement.  

Try using a combination of last clicked date, last purchase date, and zero party data when building an active segment or deciding when to suppress non-responders. 

But keep in mind that while Apple users represent a significant market share, they’re only a portion of your list.  

Senders should continue to review accurate open data provided from non-Apple Mail users to determine if any suppression algorithms are appropriate.  

7. Monitor your reputation

Reputation metrics like spam trap hits, spam complaint rates, and spam folder placement rates are all critical to help marketers understand their email list hygiene.

These metrics can be difficult to track manually. Instead, senders should consider an email success platform like Everest, from Validity, to easily monitor deliverability and reputation.  

Any changes to your sender reputation or inbox placement may indicate that it’s time to revisit your non-responder strategy using the tips we’ve outlined here.

Consequences of poor email list hygiene  

One consequence of poor email list hygiene is damage to your deliverability. This is your ability to reach subscribers’ inboxes instead of being blocked or marked as spam.

To learn how to improve your email deliverability in just a few minutes, read Validity’s “5 Minute Guide to Email Deliverability.”