Latest / The Email Marketing Podcast with Fexingo: Newsletters, Open Rates, and Subscriber Growth / How Email List Hygiene Drives Revenue
Transcript
- Lucas: Here is a number that keeps me up at night, and it is not even complicated. It is the ratio of active subscribers to total subscribers. If that number drops below seventy percent, you are not running a marketing channel; you are renting expensive real estate from internet service providers and paying rent for storage space no one uses. Luna: That feels harsh, but looking at the data from our last quarter, I see what you mean. When we have hundreds of thousands of emails sitting in a database with zero engagement in twelve months, the ISP algorithms start treating us like noise. Lucas: Exactly. And the irony is that most marketing teams are terrified to touch their subscriber lists. They treat every email address like a golden ticket because they spent money acquiring it. But in October 2026, the cost of acquiring a lead has gone up significantly across almost every vertical. Keeping someone who will never buy or click is literally draining your budget through higher sending costs and worse deliverability. Luna: So the argument is not just about vanity metrics like open rates, but about the technical health of your sending infrastructure? Lucas: It is primarily about infrastructure. Let me give you a concrete example from a mid-market software company we advised last month. They had four hundred thousand subscribers. Their open rate was hovering around eight percent, which is decent for some industries but terrible for B2B tech. They were worried about losing revenue if they cut the list. Luna: And they were afraid that deleting those addresses would hurt their growth numbers immediately. Lucas: Right. So we ran a diagnostic. We identified two hundred and twenty thousand accounts that had not opened an email, clicked a link, or engaged in any way in the last nine months. These are what I call zombie subscribers. They are not buying, but they are also not unsubscribing. They are just there, silently dragging down the sender score with every campaign we sent. Luna: I bet the fear was that if they pruned that list, the open rate percentage would spike artificially, making the current team look bad for having allowed it to stagnate. Lucas: Spot on. That is the political risk. But let us talk about the financial risk. When you send to inactive users, you are paying per impression or per transaction depending on your ESP. More importantly, you are triggering spam filters. Internet service providers like Gmail and Outlook look at engagement. If you send to ten thousand people and only five hundred open, your spam complaint rate might stay low, but your negative engagement signals tell the algorithm to put your next batch into the promotions tab or the spam folder. Luna: So by removing the unengaged, you are essentially clearing the lane for the engaged users to get seen. Lucas: Precisely. After they removed those two hundred and twenty thousand zombies, their total subscriber count dropped to one hundred and eighty thousand. On paper, that looks like a disaster. But their open rate jumped to nineteen percent. Their click-through rate doubled. And most critically, their emails started landing in the primary inbox consistently again. Luna: Did the actual revenue dip initially because they had fewer people to market to? Lucas: No. It stayed flat for three weeks while the algorithm adjusted, then it went up by twelve percent. Why? Because the people left on the list were actually interested. The conversion rate improved because the audience quality was higher. We stopped wasting resources trying to wake up ghosts and started investing in nurturing the living. Luna: This challenges the standard playbook. Most guides say grow your list as fast as possible and segment later. This suggests we should prune aggressively first. Lucas: I think it is about balance, but definitely leaning toward pruning. The mistake many brands make is assuming that silence equals disinterest. Sometimes people are just busy. Or maybe they bought a product five years ago and haven't needed an update since. We need to distinguish between dormant and dead. Luna: How do you define the cutoff? Is it six months? Nine months? A year? Lucas: It depends on your sales cycle. For a daily news newsletter, three months is too long. For enterprise software, twelve months might be acceptable. But here is the rule of thumb: if a customer has not purchased or engaged in two times your average sales cycle, they are likely lost. And if they have not even opened an email in that time, they are effectively churned. Luna: So before you delete them, you usually try a re-engagement campaign? Lucas: Yes. This is the critical step. You cannot just pull the plug. You have to give them one last chance. We design a specific sequence called the sunset campaign. It is usually three emails over two weeks. The first email asks a simple question: are you still interested? Luna: That sounds simple enough. What does the second email do? Lucas: The second email offers value. It says, hey, we noticed you haven't been here in a while. Here is a highlight of what you missed. Or here is a special offer to come back. It is not desperate; it is helpful. It reminds them why they signed up in the first place. Luna: And the third email? Lucas: The third email is the goodbye. It says, if you do not engage with this email, we will assume you no longer wish to receive our updates and we will remove you from the list. This serves two purposes. First, it prompts action. Some people will click a link saying yes keep me. Second, it clears the list automatically. Anyone who ignores it gets deleted. Luna: I love that because it puts the control in the user's hands. It feels respectful rather than punitive. Lucas: It is respectful. And it protects your brand reputation. If you delete someone silently, they might not care. But if you ask them and they ignore it, you have done your due diligence. You are not hiding behind a deletion; you are communicating a boundary. Luna: What happens if someone clicks unsubscribe during that sunset period? Do you respect that immediately? Lucas: Immediately. No questions asked. If they want out, let them out. Fighting a user who wants to leave is the fastest way to get flagged as spam. A clean list with happy users is worth infinitely more than a bloated list with resentful ones. Luna: There is also the issue of data accuracy. Sometimes these inactive addresses are just invalid or typos from years ago. Lucas: Absolutely. Hard bounces are easy to identify. But soft bounces are trickier. Over time, an email address might change domains. Someone moves from a corporate email to a personal Gmail account. By keeping them on the list, you are carrying dead weight. Cleaning the list is also an opportunity to verify email syntax and domain validity. Luna: Do you recommend doing this all at once or in waves? Lucas: In waves. If you have a massive list, pulling two hundred thousand people at once can trigger spam filters on the receiving end. They might see a sudden drop in volume and think you are a bot or a compromised account. It is safer to do it in segments based on when they joined or their last activity date. Luna: That makes sense. It maintains a steady flow of engagement signals to the ISPs. Lucas: Right. Consistency matters. Also, you should track the results of your pruning. Did the deliverability improve? Did the complaint rate drop? Usually, the complaint rate drops because you are removing people who are likely to mark your email as spam out of frustration simply because they forgot who you are. Luna: It is interesting how much this mirrors general business principles. Focus on your best customers and stop supporting the ones who don't value you. Lucas: Exactly. It is resource allocation. Your marketing budget, your creative team's time, your server capacity—these are finite. Wasting them on non-responsive audiences is inefficient. Pruning is not just a technical fix; it is a strategic realignment. Luna: If these marketing conversations have sparked something you've actually used, like deciding to clean your own list today, the way these stay ad-free is listener support. Buy me a coffee dot com slash fexingo helps us keep digging into these specific operational details for you. Lucas: We really appreciate that support. It allows us to test these theories and bring you the real-world data rather than just theoretical advice. Thank you for keeping the network going. Luna: Back to the list, though. One final thought on the sunset campaign. How do you handle the people who reply saying they are interested but haven't clicked? Lucas: Great question. Replies are high-value signals. Even a simple reply saying hi counts as engagement. Those people should be moved to a separate segment of highly engaged users, regardless of their previous history. Treat them like new leads with warm introductions. Luna: So the act of asking for permission to keep them actually revitalizes the relationship. Lucas: It does. It breaks the inertia. Sometimes people just need a nudge to remember why they subscribed. Once they engage, they are back in the game. The goal is not to have the smallest list; it is to have the most responsive list. Luna: And a responsive list is a profitable list. Lucas: Always. So my challenge to you this week is to audit your list. Find the longest inactive segment. Run a small test. See what happens when you cut the dead weight. Luna: Will you let us know if your open rates jump? Lucas: I will. And if you see a similar lift, you might just find that your revenue grows without spending a dime more on acquisition.