Open rate, once a key performance metric for email marketers, became less reliable after Apple’s Mail Privacy Protection (MPP) anonymized open tracking in 2021.
Pre-fetching inflated numbers (more on this later), obscuring true subscriber engagement.
Marketers adapted, realizing that open rates alone don’t tell the whole story. Now, new strategies and metrics are necessary to understand how audiences interact with email content.
More recently, we’ve heard from clients and others across the industry that open rates are declining. A few clients noted a corresponding drop in click rates, but overall, most reported status quo in their conversion rates. Hm…
This piqued our curiosity. Knowing that we have a depth of data and insights from our amazing partnerships, we decided to dive in to see if we could determine the reason for the recent changes. Our findings point to Apple adjusting pre-fetching timings since April 2024, leading to a reduction in pixel firing events, directly impacting open rates. Read the full story below.
Understanding tracking pixels
First things first: Since there’s no foolproof way to confirm if someone actually read an email, 1×1 transparent images, known as tracking pixels, are often used to estimate when people open messages.
Traditionally, images were loaded only when someone opened an email in their preferred platform. The platform would then request the image from its hosted URL and display it. When the transparent image is requested, it’s counted as an “open” event, assuming the email reading environment made the request.
However, privacy concerns led Google and Yahoo to add an image proxy to their webmail and email apps. Now, a server sitting between the reader and the hosting server makes the request. Senders can no longer access IP and browser data that automatically accompany image downloads.
In 2021, Apple rolled out Mail Privacy Protection in its email app. This feature functions like an image proxy, but it requests images before the person even opens the email (if they ever do), obscuring crucial “open” data that email marketers rely on to measure email engagement.
Email reading environment trends—in-depth analysis
The graph below illustrates the distribution of where emails were loaded for reading between January and August 2024. While the data skews heavily towards the North American market, it still provides a global perspective.
Looking at this data, we see that Apple’s Privacy Proxy continues to inflate tracking pixel events, often automatically, leading the distribution with 73.11 percent representation compared to other email reading environments.
This inflation primarily occurs because Apple chooses to pre-fetch images in emails when a device is connected to Wi-Fi and plugged in. This results in the sender receiving an “open” notification even if the recipient never views the email. The graph shows that from January to March, Apple accounted for about 77 percent of pixel-firing events. We’ve observed and discussed this pattern in previous blog posts and webinars.
However, the share of Apple pixel loads changed in the first week of April 2024, when pre-fetching activity decreased to about 70 percent of pixel-firing events by Apple’s Privacy Proxy. Google Image Proxy, the second most common reading environment, therefore, saw an increase in its share due to the reduction in overall pixel-firing volume. This means the overall volume of pixel firing events decreased because Apple reduced its pre-fetching activity.
We understand that the frequency of these pre-fetching requests can fluctuate. Apple’s system initiates background processes that periodically check for new emails and fetch images. This can happen multiple times, especially if a user receives many emails quickly.
We conclude that since April 2024, Apple has been adjusting when pre-fetching occurs, reducing overall pixel firing events. Since MPP fires so many pixel-firing events, our clients noticed this as a sudden drop in open rates (ESPs calculate the ratio of call pixel-firing events over sent volume) around the same timeframe, like when messages land in the spam folder.
Two additional insights stand out in our analysis. First, the graph highlights a sharp drop in MPP volume from July 25-28th. This was due to a temporary MPP outage, impacting open tracking via pixel on iPhones.
Second, and on a reassuring note, the graph shows MPP pre-fetching activity is on the rise again. Senders can likely anticipate a corresponding increase in their “open rates,” due to MPP inflating that metric.
Why opens still matter—and how to improve them
While open rates aren’t foolproof, they’re still valuable indicators of audience engagement. Remember, multiple factors can sway them. Industry-wide shifts, like the Apple pre-fetching we’ve discussed, play a part, but other factors can also influence how people interact with your email offers. To truly optimize your email strategy, let’s focus on these essential best practices:
Be friendly!
The #1 deciding factor in someone choosing to open your email is because they recognize the sender. Using your brand name is critical because that is what will register with the subscriber as familiar. Take it up a notch and implement BIMI so your logo is present as well.
A clean list is a successful list
Consider refreshing your list hygiene. Validate your audience to confirm those addresses are active and email-able. Prioritize checking addresses with low engagement (especially those without clicks). Those older, inactive ones might be abandoned, or even worse, repurposed as spam traps that put your sender reputation at risk.
Frequently fatigued?
We always recommend testing and tracking your audience to find the ideal frequency caps to avoid subscriber fatigue. Make sure your preference center allows subscribers to opt down or select their preferred message types. Most importantly, honor those subscriber requests.
Subject lines
Subject lines and pre-headers are critical for boosting open rates and overall engagement. Craft catchy subject lines and leverage the pre-header (the “second subject line”) to entice opens. Approach subject lines from your own perspective: Would YOU open that email?
Avoid bait-and-switch tactics by delivering on the subject line’s promise with relevant, engaging content. And if you’re using the same subject line approach repeatedly, consider freshening things up (e.g., changing the length, offer, or personalization) while staying true to your brand.
Test
Don’t forget the power of testing! Leverage dynamic content or A/B test subject lines, content, and even send times to discover what your audience truly enjoys. Understanding your subscribers is the key to successful email marketing.
Final thoughts
The email landscape is in constant flux, and recent changes like the reduction in Apple’s pre-fetching activity have caused noticeable drops in open rates for many senders. Staying ahead requires more than just adapting; it demands a deep understanding of the nuances affecting your email performance.
By understanding the intricacies of tracking pixels, maintaining list hygiene, and catering to your audience’s preferences, you can forge genuine connections that lead to meaningful engagement.
Remember, while open rates offer a glimpse into your campaign’s performance, it’s the combination of deliverability data, actionable insights, and a focus on building lasting relationships that truly paves the way to email success.
With Validity as your partner, you not only gain the knowledge and tools needed to navigate these complexities, but also access to our expert Professional Services team who can help you tailor solutions to your specific goals and challenges.