Designing Emails for Humans and AI in Gmail's New Era
Gmail Gemini email marketing has entered a new era. Google just inserted an AI intermediary between your brand and your customers—Gemini-powered summaries that users read before your actual content. Pair that with one-click unsubscribes, and the shift from volume tactics to customer value intelligence isn’t optional anymore.
Google just inserted an AI intermediary between your brand and your customers. Gmail’s Gemini-powered summarization now automatically distills your emails into bite-sized previews that users read before they ever see your actual content. Pair that with the new Manage Subscriptions dashboard—which publicly ranks brands by how aggressively they email—and we’re witnessing the most significant shift in email marketing since the smartphone.
Most marketers are scrambling to optimize their email structure for AI readability. That’s the wrong response. The real question isn’t how to trick Gemini into generating favorable summaries. It’s whether your emails contain genuine value worth summarizing in the first place.
Key Takeaways
- An algorithm now previews your message first. Gemini generates 1-2 sentence summaries that appear above your email. Users form impressions before seeing your creative work. Your carefully designed header image? Many recipients will never scroll that far.
- Your send frequency is now public information. Gmail’s Manage Subscriptions feature displays exactly how many emails each brand sends, ranked from most to least aggressive. One tap removes you permanently. No confirmation required.
- Relevance has become algorithmically enforced. Generic batch-and-blast campaigns won’t just underperform—they’ll actively damage your deliverability as disengaged recipients hit that one-click unsubscribe. The brands surviving this transition understand something fundamental: knowing who to email matters more than knowing how to format emails.
This guide provides actionable tips for structuring emails so that Gemini extracts the right message, while also showing how customer value intelligence transforms these tactical adjustments into sustainable competitive advantage.
How Gemini Reads Your Emails
Gmail’s summary cards appear automatically when the algorithm determines your email needs distillation. The AI scans your entire message and extracts what it considers the core value proposition—typically rendered as one or two sentences displayed prominently above your content.
Here’s what Gemini prioritizes: concrete offers, specific deadlines, clear calls to action, and factual claims. Here’s what it deprioritizes or ignores entirely: emotional appeals, brand storytelling, clever wordplay, and any key information buried below the fold. If your 30% discount appears in paragraph four, Gemini might summarize your email as a product announcement instead.
The AI also groups similar messages together, which creates an unexpected problem. If you send daily promotional emails, Gemini may stack them and highlight your oldest unread message—burying your time-sensitive flash sale beneath last Tuesday’s newsletter.
Turning AI Summaries Into an Advantage
Viewed correctly, Gemini becomes free advertising. A well-constructed email earns an AI-generated headline that communicates your value proposition before recipients invest any attention. Someone who would have deleted your email based on the subject line might engage after seeing a clear, benefit-focused summary.
The tactical approach: reinforce your key message across multiple touchpoints. Traditional email wisdom favors creative tension between subject line and preheader—one asks a question, the other teases an answer. AI optimization inverts this. Repetition increases the probability that Gemini extracts your intended message.
Traditional approach:
Subject: “What’s the perfect fall sweater?”
Preheader: “This cashmere v-neck changes everything”
AI-optimized approach:
Subject: “30% Off Fall Collection—3 Days Only”
Preheader: “30% off our bestselling fall styles”
Opening line: “Take 30% off the fall collection through Friday”
Which approach wins? That depends entirely on your audience. If most of your subscribers read email on mobile without AI features, creativity still drives engagement. If your audience skews toward Gmail’s AI-enabled interface, clarity and repetition outperform cleverness. The only way to know is to test.
The Frequency Transparency Problem
Gmail’s Manage Subscriptions feature represents something unprecedented: your email frequency is now displayed alongside your competitors’. Users see a ranked list of brands sorted by message volume. High-frequency senders appear at the top—positioned as inbox offenders rather than engaged partners.
The unsubscribe mechanism requires zero friction. One tap, no confirmation screen, immediate removal. For marketers who’ve operated on “more touches equals more revenue,” this is an existential wake-up call.
But here’s what the data actually shows: volume-based email strategies were already underperforming. Our analysis across 250+ eCommerce brands reveals that customers receiving fewer, higher-relevance emails generate 3-7x higher lifetime value than those subjected to daily promotional bombardment. Gmail’s changes simply make the failure of spray-and-pray visible to the people it annoys.
The short-term impact will hurt. Expect an initial spike in unsubscribes as users discover how aggressively some brands email. This temporarily damages sender reputation. But brands that weather the correction emerge with something valuable: a genuinely engaged list of people who actually want to hear from them.
Adapting Your Email Approach
The solution isn’t choosing between human readers and AI—both reward the same thing: genuine relevance delivered clearly. These tactical adjustments help, but remember: they’re table stakes, not competitive advantages.
1. Lead with Value, Not Warmth
Your first 100-150 characters now function as ad copy. Gemini weights opening sentences heavily when generating summaries. Every word of preamble—”Hope you’re having a great week!” or “We’ve been working on something special…”—pushes your actual offer further from the summary.
Open with the value: “Your exclusive 25% discount expires Friday at midnight.” Then add context if needed. Assume your first sentence will represent your entire email to a significant percentage of recipients.
Tips:
- Place your primary offer in the first sentence, not the third paragraph
- Include specific details: percentages, deadlines, product names
- Write your opening like a tweet: maximum information density
- Test whether your first sentence could stand alone as an ad
2. Structure Content for Machine Parsing
AI systems extract information more accurately from structured content. Clear hierarchies, explicit labels, and semantic markers help Gemini identify what matters. Buried offers in flowing prose get missed.
Rather than writing “Our spring collection launches next Tuesday and we’re offering free shipping for the first 48 hours,” structure it as “Launch date: Tuesday, March 18 | Offer: Free shipping for 48 hours.” The AI parses the second version more reliably.
Best Practices:
- Use descriptive headers that state content rather than tease it
- Format deadlines and offers with explicit labels
- Avoid image-only headers without surrounding text
- Bold critical information to signal importance to both humans and algorithms
3. Measure AI Impact Through Engagement Proxies
You can’t see what summaries Gemini generates for your emails. But you can measure their downstream effects. When AI summaries accurately represent your value proposition, engagement increases. When they misrepresent your content, you’ll see disconnects between open rates and click rates.
A/B test email structures, not just subject lines. Compare engagement between traditionally formatted emails and AI-optimized versions. If click-through rates improve while open rates stay flat, better summaries are likely driving deeper engagement.
Testing priorities:
- Subject line + body opening combinations
- Structured vs. prose formatting for the same offer
- Repetition vs. variety across subject/preheader/body
- Performance differences across Gmail, Apple Mail, and mobile clients
4. Abandon Mystery-Based Tactics
Curiosity-gap subject lines (“You won’t believe what’s inside…”) worked when you controlled the reveal. Now AI summarizes the mystery away. Gemini will extract whatever concrete information exists in your email and display it upfront—eliminating the tension your subject line tried to create.
The strategic shift: move from concealment to clarity. If your email only works when recipients don’t know what’s inside, it probably shouldn’t be sent. Treat every email as if the AI summary will accurately represent your offer—because increasingly, it will.
Strategic Recommendations:
- Replace “Something special is coming” with “25% off starts tomorrow”
- Front-load the reveal that previously came in paragraph three
- Design emails that work whether recipients read the summary or the full content
5. Build Value-Based Send Hierarchies
Basic engagement segmentation—”hasn’t opened in 30 days”—was adequate when unsubscribing required effort. Now that removal is frictionless, you need smarter criteria for who receives what.
Start by identifying your abandonment threshold: the point at which non-responders statistically never convert. For most brands, this falls between 8-12 consecutive unopened emails. Recipients beyond this threshold should be excluded from regular campaigns to protect sender reputation.
But engagement history tells only part of the story. A high-value customer who hasn’t opened recently deserves different treatment than a low-value subscriber with the same behavior. The former warrants a premium win-back sequence; the latter should probably sunset quietly.
Actionable Tips:
- Identify the engagement threshold beyond which conversion becomes statistically improbable
- Deploy high-performing creative as a final attempt before exclusion
- Weight customer value potential, not just recent behavior, in frequency decisions
- Reserve aggressive promotional cadences for audiences with demonstrated receptivity
Beyond Tactics: The Customer Intelligence Imperative
Everything above addresses how to format emails for Gmail’s new environment. None of it addresses the harder question: who should receive which emails, and why?
The uncomfortable truth is that most eCommerce brands have no idea which customers are valuable and which aren’t. They send the same promotional calendar to everyone and hope the numbers work out. Gmail’s changes expose this intellectual laziness by making frequency visible and removal effortless.
Consider a different approach. What if you could predict, with 30-80% accuracy, which customers would generate the highest lifetime value? Which were about to churn? What products would each individual most likely purchase next? Would you still send identical emails to your entire list?
Obviously not. You’d orchestrate fundamentally different experiences based on predicted customer trajectories. That’s what separates tactical email optimization from strategic customer value management.
What customer intelligence enables:
- Value-driven frequency decisions. High-potential customers receive thoughtful, personalized communication. Low-probability converters receive minimal contact—protecting sender reputation while focusing resources where they generate returns.
- Predictive personalization. Rather than showing “customers who bought X also bought Y,” show each individual the specific products they’re most likely to purchase—based on their unique value trajectory, not aggregate behavior patterns.
- Proactive churn intervention. Identify valuable customers at risk of disengaging before they stop opening emails—not after they’ve already mentally unsubscribed.
- Protected deliverability. By emailing only customers with genuine engagement probability, inbox placement improves across your entire program.
When Gemini summarizes your emails, the question isn’t whether your formatting is optimized. The question is whether there’s genuine, relevant value to summarize. Customer intelligence is the only systematic way to ensure every email contains value for its specific recipient.
The Path Forward
Email deliverability in 2025 requires earning placement in two queues: the human attention span and the AI’s summary selection. Brands that optimize for both will operate with cleaner lists, higher engagement rates, and sustainable programs that generate more revenue with less effort.
But the real winners won’t be those with the best-formatted emails. They’ll be the brands that understand individual customer value deeply enough to send the right message to the right person at the right time—automatically, at scale.
Gmail’s changes are accelerating an overdue reckoning. The era of batch-and-blast is ending. What’s emerging is an environment where customer intelligence—knowing who to email, when, with what offer, at what frequency—becomes the only sustainable competitive advantage.
The tactical guidance in this article will help you adapt to Gemini and Manage Subscriptions. Implement it. But recognize it for what it is: necessary optimization, not strategic differentiation.
The strategic question is harder: do you have the predictive intelligence to know which customers deserve which communications? Because in a world where AI summarizes your emails and displays your send frequency, the only winning approach is fewer, better emails to the right people.
That requires knowing who those people are. Not guessing. Knowing.
That’s where customer value optimization begins—and where sustainable email performance is built.
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About Releva
Releva is a unified AI-powered personalization operations platform built for mid-market eCommerce brands ($5M-$100M revenue). We replace fragmented marketing tool stacks with autonomous AI agents that orchestrate personalized experiences across email, SMS, WhatsApp, paid ads, and web—delivering an average ROI of 53x. Founded in Bulgaria, expanding globally. Learn more →
