If there’s one constant in marketing, it’s change. Every week it seems a new capability or feature is introduced in major marketing channels, adjusting expectations and creating a new best practice. One channel, email marketing, has mostly defied that convention over the last two decades. Sure, a few meaningful changes have cropped up over the years, like Gmail’s message categorization in 2013 or Apple’s Mail Privacy Protection in 2021, but email marketers haven’t faced multiple, simultaneous major changes—until now.
Over the last few years, new email service provider (ESP) deliverability algorithms have caught the attention of email marketers, but no major reactions were required. However, recent artificial intelligence (AI) capabilities have opened new possibilities for reimagining the inbox experience. Recent updates are not only changing how emails are delivered and prioritized in an inbox but also how inbox previews display messages. These updates are becoming the standard for most ESPs and mobile device mail settings, and email marketers need to adapt.
It’s time for email marketers to seize the opportunity for significant shifts in standard practices—and even consider adopting principles of search engine optimization (SEO) and social media marketing—to succeed.
Given this recent sea change, let’s explore three key new rules of email marketing.
#1: Deliver personalization or disappear
The importance of personalization in effective email marketing is well established. Initially, personalization was fueled by growing consumer expectations for individualized content experiences, and many brands have made great strides toward that objective.
In today’s marketplace, delivering more personalized email experiences is crucial to achieving visibility in recipients’ inboxes, where leading email providers are using a new relevancy-based message sorting feature. Google announced in a late March product blog posting that its relevancy-driven inbox prioritization will soon be standard for Gmail. It intends to use AI to determine each user’s most relevant messages—factoring in engagement frequency, inbox searches, and (to a lesser extent) recency of brand messages. The hierarchy closely resembles Google’s process for ranking websites in its search engine results.
In addition, Gmail, Apple Mail, and other major providers have introduced batching of messages from the same sender. Apple calls the feature digest view, and asserts that consolidating multiple messages from the same sender helps users more easily review them. This new sorting function adds complexity to staying atop the inbox because relevancy rankings don’t reset with each new message. Brands ranked as a low priority for an individual user have to overcome the deprioritization over time. Several higher-performing communications can raise the batched messages’ inbox ranking.
This is where content personalization accelerated by machine learning will pay off. Ongoing refinement of personalization through testing can help brands perfect an engagement-boosting recipe for each recipient over time.
It remains crucial to keep the sender’s reputation score at the highest-possible level by diligently exercising list management and content optimization. The new inbox dynamics put a greater emphasis on all facets of personalization—i.e., ideal frequency and format, not just content—to achieve ongoing engagement. A brand’s ability to leverage content decisioning and optimization at scale for expanded personalization will increase the likelihood of staying at the top of customers’ inboxes.
#2: Success starts with the summary
Losing control over a brand impression or conversion opportunity rankles marketers—and that’s the reality email marketers will face with AI summarization in message previews with most major email providers on newer mobile devices.
To illustrate, Apple Mail’s previews now completely dismiss the marketer-provided preheader in favor of an AI-generated summary. As shown in the example image, the message preview displayed when Apple Intelligence is enabled differs from pre-AI Apple Mail. Gmail, Yahoo Mail, and Outlook Mail are also using AI summarization as part of their inbox experience. So far, Apple Mail is the only provider that replaces the preheader with an AI-generated recap, applying summarization before a message is even opened. But, given that Apple Mail controls almost half of all U.S. email accounts, the ramifications are significant for marketers trying to increase open rates and conversions.
How does AI summarization work? And can it be influenced by marketers? While it’s easy to grasp that the summaries reflect email content, it’s difficult to predict which parts will be summarized. AI summaries have been shown to fail by completely skewing the message context. That can be comical for personal messages, but it’s an intimidating challenge for marketers aiming to share a carefully crafted brand message. So far, it appears unpredictibility in AI-generated previews is the only predictable factor, so marketers shouldn’t count on the ability to control that content.
However, marketers can take action to influence the AI summary messages, especially Apple Mail’s previews, by applying SEO practices. Here are five tactics to consider folding into your email marketing process:
- Treat subject lines like headlines: Like the primary headline on a webpage, the subject line is an email’s most prominent copy. It highlights key points for AI tools to summarize. The SEO axiom to write both for the reader and the search engine needs to be adopted for email marketing as well. Create subject lines with a dual purpose—to inform and inspire.
- Keep core messages in the live text: AI summarization scans the body content of emails, similar to how search engines crawl content to contextualize it. Thus, it’s important to ensure primary messages are contained in the live text of the email instead of just in areas that aren’t scanned by the AI, such as images or embedded modules. If text needs to be placed on top of an image (which is already not generally recommended for ADA compliance), keep the text separated from the image as an overlay.
- Use alt tags to reinforce: Since AI tools can’t read copy embedded in images, alt tag meta descriptions serve as a guide in summarization. Alt tags can provide another data point for AI summarization to draw upon for the preview or overview messages.
- Use annotations and schema markup: Annotations (nonpublic notes or labels) are primarily used by Google, and schema (structured data added via standardized coding) is predominant with Yahoo. Both of these common SEO tactics can help marketers clue in AI about the key intent of promotional emails. Currently, Apple Mail doesn’t account for these mark-ups, so it won’t influence its summarizations, but it will still assist with a decent portion of a marketing list, making it worth the effort.
- Keep writing the preheader: Google, Yahoo, and Outlook still display the marketer-provided preheader, so it’s beneficial to keep writing one for recipients who use those providers. Even though Apple Mail replaces it with an AI-formulated summary message, we surmise the preheader is still taken it into account.
For instance, if a user tends to click on promotional emails where free shipping is offered, that may be a dominant factor in the AI summaries that person sees, even if it’s not a primary offer in the message.
The takeaway is that attempts to create a uniform AI summary for all recipients will be an impossible exercise. However, that individualized AI response is another reason to deliver hyperpersonalized content that meets the demonstrated preferences for content topics and promotional offers for each recipient. The more precisely the communication content is aligned to recent engagement preferences, the more likely AI should accurately summarize a message’s key messages.
#3: Emails should be designed in viewing layers
Just as with social media, the creative content must align with the platform to be effective. For example, the way an image is sized for Instagram differs from how it’s sized for proper display on other channels. The same goes for how video uploads are previewed and viewed across various social channels. A parallel dynamic is emerging among ESPs.
One recent update with major implications for email design is Apple Mail’s new message clipping preview experiences. The practice drastically limits the visual preview, with only a small portion of the “zero scroll” area of a message shown. Users need to tap the See More button to view the entire message, creating a new barrier to earning email engagement.
This first layer of the message gives little room for the email creative to inspire, so the visible portion needs to have a distinct design purpose. Rather than leading with a large image above the primary headline, the headline should lead the message with a smaller image below it. This is illustrated in the example from Ulta Beauty, where the headline is elevated above the image to hook the recipient’s interest with what appears above the clip. This is where visual nudging principles can help effectively guide the recipient through each step of the message-viewing process.
Once the recipient chooses to see the entire message, it’s important to still consider the AI summarization opportunity presented for those who don’t want to read the entire email. All major ESPs offer this post-open AI summarization opportunity at the voluntary request of the mail user. (See Google Gemini in Gmail, which illustrates the need for post-open creative to keep the message simple and the design enticing to earn engagement.)
Also remember to weigh the quantity of offers contained in the message. The more offers presented, the greater the risk the AI summary may misrepresent the message’s primary focus.
Use these changes to your brand’s advantage
As more people upgrade their mobile devices to newer models, the ramifications of AI-influenced inbox experiences will have a greater impact on email marketing. Sure, there are ways to disable some of the new settings, but they’re not going away. The settings are active by default and will continue to evolve. It’s important for marketers to be proactive in driving the success of their campaigns by adopting, rather than passively tolerating, these new practices that guide AI features.
Look for ways these AI-fueled changes can further boost your brand’s success. For example, inbox relevancy sorting means brands that are effectively delivering personalization today will gain a greater advantage over their competitors and, potentially, see their messages stay atop inboxes for extended periods of time to boost engagement outcomes.
With AI summarization, brands can equip the AI-tailored preview or summary message to the specific interests of the recipient by prioritizing those key preferences in communication.
New message-viewing experiences, like Apple Mail’s clipping, allow marketers to leverage email design to nudge the recipient along a path that reveals messages in layers, adding excitement and intrigue in the process.
Keep finding ways to write your own rules for email marketing success with these AI-integrated features by continuously testing and optimizing your campaigns to deliver the best inbox experience for your customers, whatever mail platform they choose.
Todd Hedberg is senior director, Digital Strategy, at The Lacek Group. For more than 30 years, The Lacek Group has been perfecting the art and algorithms of brand devotion. We help world-class brands identify their highest-potential customers, engage them across channels throughout their lifecycles, personalize each relationship for optimal long-term results, and measure the true effectiveness of those efforts. The Lacek Group is an Ogilvy One company.
Illustration sources:
“Gmail’s Upgraded Search Results Help You Find the Emails You Want, Faster.” The Keyword, Google. March 20, 2025. https://blog.google/products/gmail/gmail-search-update-relevant-emails/
Nicole Merlin. “Hands-On with Apple Intelligence, Inbox Tabs & Message Summaries for iOS 18.2.” Knak. November 18, 2024. https://knak.com/blog/apple-intelligence-ios18-2/
Sarah Perez. “Gemini Will Now Automatically Summarize Your Long Emails Unless You Opt Out.” TechCrunch. May 30, 2025. https://techcrunch.com/2025/05/30/gemini-will-now-automatically-summarize-your-long-emails-unless-you-opt-out/
