Latest / The Email Marketing Podcast with Fexingo: Newsletters, Open Rates, and Subscriber Growth / How Email List Segmentation Can Backfire
Transcript
- Lucas: So Luna, I was digging into some campaign data from a mid-sized e-commerce brand we've been following, and something jumped out at me. They rolled out a pretty aggressive segmentation strategy earlier this year, and within two months their open rates had dropped by nearly 12 percent and unsubscribes nearly doubled. Luna: That sounds backwards, right? Usually segmentation is supposed to boost engagement, not tank it. What happened? Lucas: That's the thing, it's actually a pattern we're seeing more and more. They went from three broad segments to twenty-seven micro-segments — based on browsing behavior, past purchases, even the time of day they opened emails. And they were sending a different campaign to each group almost every day. The result was that most people got fewer emails, but the emails they did get felt repetitive and oddly impersonal, because the segments were so narrow that the content got repetitive fast. Luna: So they traded one problem for another. Less volume but more noise. Lucas: Exactly. And it's a reminder that segmentation isn't a silver bullet. We've talked a lot on this show about how segmentation can boost revenue, and we've seen that, but there's a flip side. When you over-segment, you can actually exhaust your list. I call it 'list exhaustion.' Luna: List exhaustion. That's a great term. And it kind of ties into something we've been thinking about with the show itself. You know, we put a lot of effort into making these episodes useful, and we often wonder if what we're doing actually helps people. If you've ever learned something from a Fexingo show that you've put to work, we'd love to hear about it. And if you want to keep these conversations going ad-free, you can support us at buy me a coffee dot com slash fexingo. That's buy me a coffee dot com slash fexingo. It's a small way to keep us going, and we appreciate every bit of it. Lucas: Yeah, and we're grateful for anyone who does. But back to segmentation. So this brand's experience fits a broader trend I've been noticing. A lot of marketers assume that more segmentation equals better personalization, but the data suggests there's a sweet spot, and overshooting it can be worse than doing no segmentation at all. Luna: What's the sweet spot then? Or is it more about how you segment rather than how many segments you have? Lucas: I think it's both. Let's talk about the how first. The problem with this e-commerce brand wasn't just the number of segments. It's that they segmented on behaviors that didn't actually correspond to different content needs. They had a segment for people who viewed a product page for more than thirty seconds, another for people who viewed it for less than thirty seconds. But both groups got essentially the same follow-up email with a slightly different subject line. So the personalization was superficial, and customers felt it. Luna: So the content didn't really change, just the labels. That would get old fast. Lucas: Right. And then there's the volume issue. When you have twenty-seven segments, you need enough content to fill each of those streams. That means you're either recycling the same offers, or you're stretching your creative team thin, so the quality drops. The customers aren't stupid — they notice when the 'exclusive' email they get is basically the same as the one they saw last week under a different header. Luna: So what's the fix? Do they just cut back to three segments and call it a day? Lucas: Not exactly. The fix is to segment based on what actually drives a different response — not just demographic or behavioral data, but the job the email is doing for the customer. For this brand, what worked wasn't more segments, it was fewer, better-defined segments. They consolidated down to six: new subscribers, repeat buyers, lapsed buyers, high-value customers, window shoppers, and a general catch-all. And they sent each group a distinct editorial calendar — not just different subject lines, but genuinely different offers and information. Luna: And that reversed the decline? Lucas: Yeah, within a quarter open rates were back up to their old baseline, and revenue per email actually increased by about 14 percent. But the bigger lesson is about the temptation to over-engineer. I've seen this happen across industries, and it's not just e-commerce. It's B2B SaaS, it's media newsletters, it's anyone who thinks more data is automatically better. Luna: I wonder if there's a parallel to what we talked about in episode 163, why segmentation is overrated. But this seems like a different angle — not that segmentation is bad, but that it's easy to overdo it. And we should mention there's a real cost to over-segmentation beyond just engagement: it can hurt deliverability. Lucas: That's a crucial point. When you send more emails to smaller segments, your overall engagement rates can drop, and that feeds back into your sender reputation. In this case, they also saw their spam complaints go up, which is a double whammy. So you're not just annoying people, you're potentially getting your emails blocked or sent to the promotions tab. Luna: Right, and that's a long-term problem. Even if you fix your segmentation, if your domain gets flagged, it takes a while to recover. Lucas: Exactly. And that's why I think the concept of list exhaustion is so important. It's not just about spam complaints — it's about the psychological fatigue of being contacted too frequently and too narrowly. We all know the feeling of getting an email that's clearly trying to be relevant but just misses the mark. It actually makes you trust the brand less, not more. Luna: So how do you know if you're over-segmenting? Is there a red flag, like a metric that tells you it's time to pull back? Lucas: The biggest red flag is a rising unsubscribe rate even when your open rate looks stable. That suggests people aren't bothered enough to stop opening, but they're bothered enough to leave. Also, watch your reply rates. If you're getting more 'unsubscribe me' replies or negative replies, that's a signal. And if you see your list growth slowing even though your acquisition efforts haven't changed, over-segmentation could be the culprit. Luna: Because people are silently leaving, not just clicking unsubscribe. Lucas: Exactly. And that's the worst kind of churn, because it's invisible. So the practical advice is to start with a small number of segments — maybe three to five — and only add a new one when you have a clear hypothesis that it will lead to a different outcome, and when you have enough data to support it. And always test, A-B style, to see if the extra segment actually improves your key metrics. Luna: That reminds me of a rule I read about: 'Segment when the cost of the segment is less than the revenue it generates.' Seems simple, but it's hard to calculate. Lucas: It is, but you can approximate it. The cost includes not just the creative and sending costs, but the opportunity cost of cannibalizing other segments — because if you're sending more emails to one group, you might be annoying them and reducing their lifetime value. So you have to look at long-term revenue, not just immediate open and click rates. Luna: I think one of the most surprising things from this case is that they saw a revenue increase after they cut segments. That flies in the face of a lot of conventional wisdom, which says more personalization always wins. Lucas: It does challenge that, but it also makes sense if you think about it from the customer's perspective. They don't care how many segments you have. They care about receiving emails that are useful and not overwhelming. Sometimes less is genuinely more. Luna: So what's the takeaway for our listeners? If they're currently over-segmenting, where do they start? Lucas: First, audit your current segments. Look at the last sixty days. Are there any segments that have fewer than, say, a couple hundred people? Are there segments that get similar open rates to each other? If so, you probably don't need them. Second, look at your send frequency. If you're sending to some segments more than twice a week, and they're not high-value, you're likely doing damage. And third, run a test: take your bottom-performing 20 percent of segments and consolidate them into a single 'general' segment. See what happens to engagement and revenue over the next month. Luna: That's a solid plan. And it's not just about cutting, but about being more thoughtful about why you're segmenting in the first place. Lucas: Exactly. The goal of segmentation isn't to have the most segments. It's to send the right message to the right person at the right time. And sometimes the right person is a broad group that shares one clear interest or need, not a micro-group that shares thirty behavioral traits. Luna: I think we should do a follow-up episode on how to actually test segmentation. That could be useful. Lucas: That's a great idea. We'll add it to the queue. For now, though, I hope this gives people permission to pull back and simplify. The data is clear: over-segmentation can backfire, and list health is about more than just keeping your list clean — it's about keeping your relationship with your subscribers healthy. Luna: Well said. And if anyone has their own over-segmentation story, we'd love to hear it. You can find us on social or drop a note in the show notes. Lucas: We'll be back next week with another deep dive. Until then, keep your segments lean and your emails useful.