In ecommerce, blasting the same message to everyone just doesn’t work like it used to. When customer expectations are high, and competition for eyeballs is even higher, proper segmentation is the difference between getting ignored and getting results. Instead of shouting into the void, a good email segmentation strategy lets you speak directly to the right people.

When done right, email list segmentation can dramatically boost engagement, reduce unsubscribes, and increase revenue. That said, it’s just as easy to do segmentation wrong as it is to do it right. 

In this article, we’ll break down five of the most common mistakes marketers make when segmenting email lists, how they can sabotage your campaigns, and how to fix them. 

Why is Segmentation Important in Email Marketing?

In short, segmentation is important in marketing simply because generic messages get ignored. Without segmentation, you're essentially shouting into a crowd and hoping someone listens. With segmentation, you're speaking directly to the right person with the right message at the right time.

Segmented campaigns consistently outperform their generic email counterparts. In fact, data from Mailchimp shows that segmented emails have a 14.31% higher open rate and 100.95% higher click rate than non-segmented campaigns. 

The reason? People are more likely to engage with content tailored to their interests or behaviours. No one wants to read emails that don’t apply to them.

Personalized communications make people feel like you understand them, their interests, and their needs, fostering customer loyalty and influencing purchasing behaviours. At a time when customer acquisition costs and competition between brands are high, a good email segmentation strategy can seriously increase your ROI. 

Common Email Marketing Segmentation Mistakes

A good email marketing segmentation strategy starts with properly splitting up your master contact list for the best results. While anyone can set up a few lists, marketers make a few common mistakes when segmenting email lists that should be avoided when targeting customers this way. 

1. Segmenting Too Much (Or Not Enough)

Marketers often get caught up in one of two extremes when it comes to customer segmentation: oversegmentation or undersegmentation. Creating overly specific, tiny segments in an attempt to hyper-target will often work against you. 

Many brands segment their lists into groups so small that campaigns reach barely anyone. Often, this stems from concerns about deliverability or a desire to get high open rates on each send. Marketers think sending only to the “most engaged” few will keep metrics high, but high email metrics don’t matter much if your sales numbers and ROI aren’t strong. 

On the other hand, undersegmenting can also be detrimental to your marketing efforts. When building your email marketing campaigns, you must consider who should receive your content and why. If you plan to do some geographic segmentation, you should have a reason that makes sense–maybe you sell winter coats and only want to target states/provinces that get cold, for example. 

Sometimes, splitting by demographics or behaviour isn’t specific enough for your goals, and this undersegmentation can lead to email fatigue, which directly translates into unsubscribes. Engaged customers get frustrated by irrelevant content, and less active subscribers disengage further or unsubscribe altogether, hurting your numbers and wasting the money and energy you put into acquiring their emails to begin with. 

2. Segmenting Without a Purpose 

Similar to undersegmenting, a major part of proper segmentation includes being able to feed relevant content to your audience. If you’re creating audience groups without intention, there’s no point to your campaign. 

When segmenting your audience, consider these two purposes: 

1. Does the segment offer some kind of personalization for the end user? 

2. What insights will your business gain from this audience? 

It might seem exciting to split your audience by x, y, and z, but if you don’t have relevant emails planned and specific goals you would like to achieve by segmenting your audience this way, it might be better not to bother until you do. 

3. Never Excluding Contacts

Every marketer has had that one boss who insisted they “spray and pray” when it comes to marketing emails. However, failing to exclude certain subscriber groups from specific email sends can result in lower deliverability. Many marketers either don’t set up exclusion segments or forget to use them when they should, leading to bad delivery rates and worse engagement. 

Remember, the goal of segmentation is to ensure that not everyone gets every email, including people for whom that message is inappropriate (recent buyers, support cases, unengaged contacts, etc.).  

Continuing to email chronically unengaged or bounce-prone addresses will drive up bounce rates and lower your sender reputation, increasing the risk that more of your emails will land in spam. This is why it’s so important to regularly prune or exclude these segments to keep your deliverability healthy.

Finally, if you have a customer with an open support ticket, for example, sending cheery marketing emails can seem tone-deaf. No one wants to further irritate someone who is already unhappy. 

4. Not Personalizing Content to Each Segment

As we hit on earlier, you don’t want to segment without a purpose. Similarly, you don’t want to segment and then not create any personalized emails that are relevant to the demographics or behaviours you’re segmenting by. 

Collecting tons of customer data like preferences, demographics, purchase history, “zero-party” data from quizzes or sign-up forms, etc., but then not using it to tailor email content for different customer segments is a missed opportunity. Many brands ask subscribers for information like gender, interests, or size preferences to enrich their profiles, yet still send everyone the same generic email. 

Failing to use available data undermines the entire point of segmentation, which is to increase relevance. It can result in lower engagement and conversion rates, even if your targeting segments are otherwise well-defined. Essentially, you’re leaving money on the table by not customizing offers and content to each segment’s needs.

Think about it–if you know that your customer told you via your “welcome” pop-up that they use single-serve coffee pods, you shouldn’t be sending them promo emails for whole bean coffee. Use the information you have, exclude them from irrelevant communications, and instead create something that better suits them. 

5. Ignoring the Buying Cycle

Consider which phase of the buying cycle your contacts are in before sending them any communications. People who have recently made a purchase might not want to see any more marketing emails until they’ve had a chance to receive and try their items, but they might enjoy a timely email with an add-on offer if they claim it before their order is processed.  

This could also backfire if they receive a “25% off” offer on the item they just bought a few days ago at full price. Sending promos while a customer is already enrolled in a post-purchase email flow increases the amount of emails they’re receiving from your business and can be grating when they’re not relevant. 

The fix? Define a sensible blackout window (e.g. no promos for 7 days post-purchase, or until the customer has received their order). Instead of lumping them into every sales email, put recent customers on a different path: focus on enhancing their post-purchase experience. For example, send a follow-up thanking them for their purchase, provide helpful content about the product, or suggest complementary items after they’ve had time to enjoy their purchase

How Klaviyo Helps You Avoid These Segmentation Pitfalls

At Blue Badger, we love recommending Klaviyo to clients looking to up their email engagement and personalization game. Klaviyo’s platform is built to make email marketing segmentation easy and effective. It allows you to segment customers using any data from any source, whether it’s demographic info, past purchases, website behaviour, or custom properties.

One of Klaviyo’s strengths is that segments update automatically in real time. As soon as a customer’s behaviour or profile changes, if they meet (or no longer meet) your segment conditions, Klaviyo will include or remove them from the segment. This helps prevent both over- and under-segmentation issues. For example, you don’t have to manually prune unengaged users – you can set a segment like “Engaged Last 90 Days,” and it will always stay up to date.

With Klaviyo, you can easily create different content for different customer segments by using dynamic blocks or segment-specific campaigns. For example, within a single campaign, you can swap in product recommendations based on a recipient’s past purchases or show a different hero image depending on segment membership.

To further help brands avoid segmentation mistakes, Klaviyo has introduced features like Segments AI. This tool lets you describe the customers you want to target in plain language, and the AI will build the segment logic for you. It used predictive analytics (e.g., churn risk, customer lifetime value) and machine learning to suggest smart segments you might not have considered, or to speed up the creation of complex audience splits.

Conclusion

Ultimately, the primary objective of ecommerce marketing is conversion. By properly tailoring email content for different customer segments, businesses can present products, offers, and information that align with individual needs and preferences, directly driving sales and increasing revenue per recipient.

When customers feel understood and valued because their communications are relevant to their specific needs, it deepens their connection with the brand. This strengthened relationship leads to increased customer lifetime value (CLV) and a higher likelihood of repeat purchases.

As a Klaviyo partner, we at Blue Badger have the skills and experience you need to get started creating email segments that can lead to better email marketing and increase your ecommerce business’s ROI. Get in touch today to learn more about email marketing with Klaviyo.