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Last updated on
November 10, 2025
The ping of a new email arriving in the inbox. That’s the one from the frozen foods retailer. But, er... The subject line is “Frozen Meatballs—30% Off” for the vegan eater. Well, this is awkward, to say the least... That was one of the catastrophic email segmentation mistakes. And it actually made the customer freeze in bewilderment, or even dump the brand for the competitor (who, by the way, sent the properly targeted email). In fact, nearly half of people (43%) unsubscribe from newsletters due to irrelevant content.
Despite the best intentions of email marketers, wrongly segmented emails still occur. And such blunders are more common than you can imagine. But don’t worry, each flaw can be fixed. And we know how. Follow this guide.
To put it simply, email segmentation is a thorough sorting process. It presupposes breaking down the list of your subscribers into groups (segments), based on what they like/dislike, where they are in the customer lifecycle, when exactly they shop, and so on.
When these segments are properly defined, they allow you to create a customer newsletter that speaks directly to each group’s interests and needs. Instead of a generic blast, the message feels tailored and personal.
After you’ve successfully done that to your email list, you can win your customers over while also reaping these benefits:
And finally, stop sending luxury house listings to those who can’t afford them, if you’re in real estate (or meat products to your vegetarian or vegan customers if you’re in the food industry). How? By targeting your emails to the proper customer segment.
Learn the fundamental methods that will help you avoid fatal mistakes in email segmentation and adequately group subscribers into the right customer segments.
For example:
Let’s look at the case of B2C email marketing based on demographics, specifically the date of birth and gender. First, YOOX congratulates the male customer on their birthday. Second, the brand features only male-relevant products after the CTA, “Add to dream box.”
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For example:
To get a picture of technographic segmentation, check out this SaaS email, targeting those companies and “teams who use Slack.”
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Let’s start with one of the extremes: insufficient or under-segmentation, which is one of the most commonplace mistakes in email segmentation.
Suppose you actively target cart-abandoners (segmentation by behavior). So, you send abandoned-cart emails and think that it’s enough. Quite fairly, you do convert them back to their shopping carts. But that’s far from enough. You’re missing other customer segments for effective email marketing.
At other times, email marketers take only one geographic or demographic criterion. In most cases, it’s a zip code or gender.
For example:
The German fashion brand segments the newsletter subscribers into only two categories: “Men” and “Women.”
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How to fix it:
If you segment customers directly from the sign-up form, make sure to add two or three (not more) email segmentation factors.
For example:
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That’s what Acefone did to segment B2B leads firmographically (based on the number of users and product interest) and geographically (by location).
Alternatively, to avoid overwhelming people with too many fill-in fields during the subscription process, create a poll or survey email to categorize them into groups later.
For example:
Let’s learn from Healthline, a healthcare information provider, offering a newsletter poll for psychographic segmentation: “What kind of content interests you most?”
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Now, over to another extreme (and another email segmentation mistake).
Yes, we can’t deny the benefits of email list segmentation. But overdo it—and there you have it: 57 micro-lists and zero time to design creative newsletter copies and tailor email content to each subscriber segment.
How to fix it:
Prioritize the most impactful customer categories, not microscopic ones. In this context, five to seven would be a wise choice to outperform tons of hyper-specific ones. These can be:
Yet, one or two should be given the top priority.
For example:
Sustainability-first buyers represent one of their key email segments (based on psychographics) for Ninja Transfers. Here’s one of the targeted email campaigns from the DTF transfer company, featuring sustainable blank T-shirts for the eco-conscious customer segment.
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Not all email recipients are equally active. They may never react to your marketing emails or newsletters as if they were in “sleep mode.” And once you launch a promotional campaign for your segmented email list with inactive subscribers, you (again) make one of the biggest email segmentation mistakes. And your rates (whether the open rate or the conversion rate) sink like a stone.
How to fix it:
The fastest way to wake up the “sleepy” or quiet segments is win-back or re-engagement emails like these from different brands:
For example:
Let’s peek into B2B email marketing. See how Sprout Social re-engaged the inactive client segment: “It’s been a while since we’ve been in touch.”
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Here’s another example (this time in B2C) with a personalized coupon code from ModCloth: “Wait, Come Back
Here’s 40% OFF.”
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Some customer segments would savor every word of your newsletter as if it were a personal love letter. Others are skimmers who quickly scan it for the key highlights (or sweet deals and discounts) and bounce.
Some prefer static email content formats that don’t distract. Others would love to actively engage with your newsletters by playing a game or moving a slider (e.g., a before-and-after slider with the new lipstick shade applied if it’s a cosmetics brand).
How to fix it:
Run email A/B tests and segment customers by engagement (opens, read-throughs, clicks-throughs, etc.):
For example:
Take a glimpse at several email examples for travel. Contiki crafts more dynamic, interactive emails for those segmented customers who are more likely to buy through gamification. The travel agency embeds engaging spin wheels, such as this spin-to-win game.
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At the same time, they offer motionless guides like this: “Travel hacking 101: top tips to travel cheaper this year.”
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Do you still use the same email segments as you did years ago?
Oof, it’s one of the worst mistakes in email segmentation. Let’s face it: Preferences and priorities—both your customers’ and yours—change and evolve over time. What worked last year (or even last quarter) is no longer effective in converting specific subscriber segments in email marketing today. But also, your business might have a different priority at the moment.
How to fix it:
A practical way to approach re-segmentation is to periodically re-prioritize the most valuable customer groups. For example, a brand selling wooden products shifted its focus toward a new priority segment—pet owners purchasing wooden accessories for their pets.
In addition to identifying new high-value groups, it is also effective to re-segment or remove inactive subscribers from the list. This approach helps save time, reduce costs, and improve overall campaign performance.
In other words, stay flexible: re-prioritize and re-segment regularly. You may also ask your email subscribers to update their interests and preferences, just like Joybird did.
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“Male, student, 18–24, prefers yellow CTA buttons, gets converted only amid back-to-school email campaigns…” What else?
It’s not a person—it’s a data point.
Your email audience shouldn’t be just a bunch of data points like the ones above. Otherwise, you’ll lose customer trust (and customers overall) due to this email segmentation mistake.
How to fix it:
Take a page from Grant Aldrich, Founder of Preppy. The education business owner is all for humanizing emails. He notes, “Even when you send emails to a segmented list, make sure people feel like you actually see, understand, and value them, not their purchase history or age. Storytelling with human touch is the quickest and most authentic way to establish such a meaningful personal connection with customers.”
And here are several actionable tactics you can apply to your segmented emails to achieve humanization and personalization, too:
For example:
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Here’s a personalized email from Grant Aldrich with the customer’s name and “the story of a student who was a gig worker and was looking to switch careers.”
Why suffer?
Segmenting your email subscriber list manually is like chopping onions—tears all over the place. You simply miss out on significant data (like behavioral patterns) and get lost in tons of other information. And that’s yet another email segmentation mistake to watch out for.
How to fix it:
Smart email segmentation always starts with understanding customer intent. In this context, a keyword research tool can reveal what your customers actually search for. Those insights will show clear intent and help you categorize people by their exact interests.
Then, you can implement website behavior trackers (take Mouseflow or Clicky) or tools like heatmaps (take Hotjar or Humblytics). That’s how you build smarter, tighter segments.
No need to sift through tons of spreadsheets with your bare hands.
Mailmunch empowers you with absolute email marketing automation to put everything on autopilot:
Because the only thing worse than poor segmentation is... doing it by hand.
So, if you haven’t yet tamed that wild beast called “email list segmentation,” don’t panic. You are not alone. Even the best marketers have sent a few “oops” emails before nailing the perfect subscriber segments at least once.
The happy ending? Mailmunch can help you spot and fix those errors in the blink of an eye—automatically. Sign up today and let your email campaigns always be well segmented and customers incredibly satisfied (and converted to buy!).
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