Summary
The recent trend of increasing email open rates, particularly observed since September, has sparked discussion among email marketers and deliverability experts. This surge is largely attributed to the evolving behaviors of Mailbox Providers (MBPs) like Google, Yahoo, and Apple, which increasingly pre-fetch or cache images in emails. While on the surface this might seem like a positive sign for engagement, it fundamentally alters the reliability of open rates as a key performance indicator (KPI), making it crucial to understand the underlying causes and adjust analytical approaches.
Key findings
- Pre-fetching increase: There's a noticeable increase in image pre-fetching by services like GoogleImageProxy, leading to higher reported opens that aren't necessarily true user engagements.
- Distorted metrics: These automated opens inflate open rates, making the metric less accurate for measuring actual recipient interaction. This highlights why open rates are often not considered a truly accurate KPI. You can learn more about this in our article on the reliability of open rates as a KPI.
- Inbox placement signal: While inflated, a pre-fetched open still indicates that the email likely landed in the recipient's inbox and their mailbox is active, as opposed to being blocked or sent to spam.
- Possible reputation improvement: An increase in pre-fetching might indirectly suggest an improvement in sender reputation, leading to more emails being delivered to the primary inbox instead of promotion tabs or spam folders.
Key considerations
- Shift focus to clicks: With opens becoming less reliable, marketers should pivot their analysis to metrics that directly reflect user engagement, such as click-through rates (CTR) and conversions.
- Trend analysis: Even with inflated numbers, open rates can still serve as a trending metric to observe significant shifts in deliverability, rather than absolute engagement figures. Understanding how opens should be used as a metric can help.
- Data interpretation: It's essential to understand the underlying mechanics of how mailbox providers process emails to correctly interpret your marketing data, as discussed in this article from Microsoft on rethinking email metrics.
- MTA adaptation: Email service providers (ESPs) and Mail Transfer Agents (MTAs) may need to update their tracking mechanisms to better differentiate between bot-driven and genuine user opens, or at least provide clear categorization.
What email marketers say
Email marketers are increasingly grappling with the challenge of accurately interpreting open rates in light of new pre-fetching mechanisms. Many express frustration over the 'garbage data' that obscures actual engagement, forcing them to reconsider what an 'open' truly signifies for their campaigns. The sentiment is generally that while an increase might superficially appear positive, it necessitates a deeper dive into other metrics for meaningful analysis.
Key opinions
- Data garbage: Many marketers view the inflated open rate data, especially from GoogleImageProxy, as misleading or 'garbage' that doesn't reflect actual user engagement.
- Inflated MPP: The increase in pre-fetching seems to apply not only to traditional bot activity but also impacts Mail Privacy Protection (MPP) opens, suggesting a broader change in how Gmail handles emails.
- Shifted deliverability: A sudden, significant jump in open rates might indicate improved deliverability, such as emails moving from promotion tabs or spam folders into the primary inbox.
- Beyond opens: Marketers are increasingly recognizing that opens are not a true indicator of engagement and are seeking other metrics for performance evaluation. For more on this, see how to explain poor performance despite good open rates.
Key considerations
- Monitoring user agents: While not a definitive solution, identifying specific user agents like Mozilla/5.0 ... GoogleImageProxy can help categorize opens, even if they aren't excluded from the total.
- Adjusting KPIs: Marketers must adapt their KPIs to focus on actions that clearly demonstrate user interest, such as clicks, conversions, and replies. This is part of a broader trend of rethinking deliverability metrics.
- Engaging with ESPs: It's beneficial to communicate with ESPs and MTAs (like GreenArrow) about these changes to see if they are updating their tracking or reporting methods. This article from Benchmark Email discusses the continued relevance of open rates, but also the nuances.
- Focus on deliverability: Ultimately, the goal is inbox placement. If high opens correlate with increased click-throughs, it may still indicate successful delivery and a healthy list, even with automated opens.
Marketer view
Email marketer from Email Geeks observes a significant increase in open rates since early September, noting that their Mail Transfer Agent (MTA) doesn't classify these new opens as Mail Privacy Protection (MPP) despite a common Google Image Proxy user agent. This raises questions about how to interpret the data, especially as the volume of these opens is very high, suggesting a new behavior from Google's caching system.
Marketer view
Marketer from AgencyAnalytics suggests that while open rates are a crucial metric, they should be viewed as one piece of the puzzle, revealing overall engagement and the effectiveness of subject lines. They indicate that despite pre-fetching, this metric still offers valuable insights into initial campaign performance.
What the experts say
Deliverability experts generally agree that the concept of a 'true' open rate has become largely obsolete due to pervasive image pre-fetching by major mailbox providers. They emphasize that while these automated opens can make the data appear 'garbage,' they still convey valuable signals about inbox placement. Experts advise marketers to accept this new reality and focus on more reliable engagement metrics, while cautioning against over-analyzing the open rate in isolation.
Key opinions
- Garbage data: Experts universally agree that open rate data, particularly with pre-fetching, should be treated with extreme caution, as it often constitutes 'garbage data' that obscures genuine user interaction.
- Masking real opens: Mail Privacy Protection (MPP) and similar pre-fetching technologies are designed to mask actual user opens, making it intentionally difficult for senders to determine true engagement.
- Inbox confirmation: Despite the distortion, a pre-fetched open still indicates that the email was successfully delivered to the recipient's inbox and that the mailbox is actively checking for new mail. This is a crucial signal for deliverability.
- Holistic view: Instead of focusing on opens, experts recommend a broader analytical approach, considering other metrics like click-through rates, conversions, and subscriber feedback to gauge campaign success.
Key considerations
- Accepting the new normal: Deliverability experts advise marketers to accept that precise open tracking is a thing of the past and to adjust their measurement strategies accordingly. This includes understanding the reasons why emails fail based on other signals.
- Focus on deeper metrics: Emphasis should be placed on clicks, conversions, unsubscribes, and spam complaints as more reliable indicators of campaign performance and audience health. Read more on what's wrong with the open rate in email marketing.
- Trend over absolute: Use open rates for general trending analysis, observing significant shifts rather than fixating on the exact percentage. Sudden spikes (or drops) can still signal deliverability changes.
- Investigate anomalies: While opens are imperfect, investigating unusual changes can sometimes reveal important shifts in how mailbox providers are handling your mail, as SpamResource frequently highlights in its analyses.
Expert view
Deliverability expert from Email Geeks states that image pre-fetching is common among major email providers like Google, Yahoo, and Apple. They explain that this process automatically loads images within an email, regardless of whether the user actually views the message, leading to an open being registered.
Expert view
Expert from Word to the Wise suggests that an increase in opens could mean an improvement in deliverability, such as emails no longer going to the spam folder or promotions tab. This implies that if a sender's reputation improves, more of their images may be pre-fetched, contributing to higher reported open rates.
What the documentation says
Official documentation from major mailbox providers and industry standards often outlines how email is processed, including security measures that can influence reported open rates. While they may not explicitly detail every instance of pre-fetching, the move towards privacy-enhancing features and spam filtering implicitly leads to automated interactions with email content. This means that a 'delivered' email might trigger an open even if a human recipient hasn't yet seen it, reflecting a technical validation rather than active engagement.
Key findings
- Privacy features: Documentation for services like Apple Mail Privacy Protection (MPP) confirms automatic image loading to protect user privacy by masking IP addresses, inherently inflating open rates.
- Security scanning: Mailbox providers routinely scan incoming emails for malicious content, often involving the automated rendering of images and following of links, which can register as opens without human interaction.
- Inbox placement confirmation: The fact that an image is loaded, even by a proxy, confirms that the email has successfully navigated various filters (like SPF, DKIM, DMARC) and reached the intended inbox. This is a positive sign for email authentication and overall deliverability. Learn more about DMARC, SPF, and DKIM.
- Evolving metrics guidance: Some documentation and industry bodies increasingly advocate for marketers to prioritize metrics beyond opens, such as clicks, conversions, and subscriber feedback, to measure true engagement. This aligns with advice on leveraging tools like Google Postmaster Tools for deeper insights.
Key considerations
- Technical understanding: Marketers should have a basic understanding of how email infrastructure and privacy features, as described in technical documentation, impact their reported metrics.
- Adaptation of tracking: Email service providers are continually updating their tracking methods to account for these changes, but complete accuracy for 'true' opens remains elusive due to privacy initiatives. This is part of the ongoing challenge in defining and using the email open rate KPI.
- Focus on deliverability signals: Instead of obsessing over open rate numbers, it's more productive to ensure strong deliverability through proper authentication and good sending practices. This affects more important metrics.
- Holistic performance review: Documentation often implies that no single metric tells the whole story. A comprehensive view of email performance should include deliverability rates, click-through rates, conversion rates, and unsubscribe rates. Microsoft's blog on rethinking email marketing metrics is a good example.
Technical article
Documentation from Microsoft Dynamics 365 explains that email clients, including their own, implement image pre-fetching to improve user experience and security. This often means that an email is opened automatically to load content or scan for threats, registering an 'open' before a user even sees it.
Technical article
AgencyAnalytics' KPI definition of email open rate clarifies it as the percentage of recipients who opened an email campaign, but implicitly acknowledges the complexities introduced by modern email client behaviors. They imply that while the formula remains simple, its interpretation requires deeper context.
Related resources
10 resources
Related pages
Why are Yahoo and AOL email open rates suddenly lower?
Why do all-image emails have higher open rates and are open rates a reliable KPI?
How should opens be used as a metric for email marketing?
What causes a sudden drop in email open rates?
Why am I seeing a sudden spike in Gmail email open rates?
How do I explain poor email performance despite a good open rate?
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