Latest / The Email Marketing Podcast with Fexingo: Newsletters, Open Rates, and Subscriber Growth / How Email List Temperature Affects Your Sender Reputation
Transcript
- Lucas: So, Luna, you know how we always talk about list size as this vanity metric? I think it's time we talk about something a little more abstract but arguably way more important: the temperature of your email list. Luna: Temperature? You mean like, whether your subscribers are hot or cold? That's not a new concept, but I bet there's more to it than just that. Lucas: Right, and it's actually a term some email deliverability folks use. The idea is that your list has a thermal signature based on how engaged your subscribers are, how fresh the addresses are, and how consistently you're sending. And that signature is a big part of what Internet service providers use to decide whether your email lands in the inbox or the spam folder. Luna: So it's basically a measure of trust. If your list is lukewarm, ISPs get suspicious. That makes sense. And I guess that's why we should be thinking about this more deliberately. Lucas: Exactly. And before we dive deep, I have to say — if this episode helps you think about your list in a new way, and it was worth a coffee to you, there's a link for that: buy me a coffee dot com slash fexingo. It's a small way to keep these conversations going without ads. Luna: Yeah, we appreciate that, genuinely. And it does help us stay independent. Lucas: So, let's get into the mechanics. The first thing to understand is that every email you send is a signal. When someone opens, clicks, replies, or even moves you to their primary tab, that's a positive signal. When they delete without reading, mark as spam, or just ignore you for months, that's a negative signal. Your list temperature is essentially the aggregate of all those signals. Luna: And ISPs are constantly monitoring those signals, right? So a cold list is going to hurt your reputation even if you have a million addresses. Lucas: Yes, and that's why we see companies with huge lists struggling to get a 20 percent open rate, while a smaller, hyper-engaged list might see 60 percent or more. The size isn't the problem; the temperature is. Luna: What's the most common way lists go cold? I'm guessing it's just neglect — people don't send for a while, or they buy lists, but even organic lists can cool down. Lucas: The biggest culprit is inconsistency. If you're sending a weekly newsletter and suddenly you go silent for two months, those subscribers start to forget who you are. When you finally send again, they might not open, and that's a negative signal. But there's also the issue of list growth without engagement. You know, running a giveaway and collecting a ton of emails from people who don't actually want your content. Luna: That's a real trap. It feels good to see the number go up, but you're basically adding cold water to a warm bath. Lucas: Exactly. So, let's talk about a concrete example. I was reading about a B2B SaaS company that had a list of about 50,000 subscribers. They were sending a monthly newsletter, and their open rates had slowly drifted down to 12 percent. Their click rate was under 1 percent. They were technically hitting inboxes, but barely. Their list temperature was lukewarm at best. Luna: What did they do? I bet they didn't just start sending more emails. Lucas: Right, they did a full temperature check. They looked at engagement over the past 90 days, separated their subscribers into active, inactive, and cold segments, and then they ran a re-engagement campaign for the inactive group. After two emails with no response, they sunset those addresses — meaning they automatically removed them from the list. They lost about 15,000 subscribers in a month. Luna: That's a brave move. But I'm guessing their deliverability improved a lot. Lucas: It did. Within a few weeks, their open rates jumped to 38 percent, and their click rate tripled. More importantly, their sender reputation score went from a middling 80 to over 95. And their actual revenue from email increased, because they were only reaching people who wanted to hear from them. Luna: So it's not just about avoiding the spam folder; it's about making every send more effective. That's a great example. Lucas: Exactly. And this concept of temperature isn't just for B2B. I've seen retail brands do the same thing. One clothing retailer found that cart abandonment emails to 'cold' segments were getting essentially no clicks, but when they focused on subscribers who had opened in the last 30 days, they saw a 21 percent click to open rate. So they changed their trigger logic to only send to warm segments, and they saw a significant boost in revenue per email. Luna: Interesting. So how do you actually measure the temperature of your list? Is there a metric for that? Lucas: There isn't a single number, but you can approximate it by tracking a few key metrics. The most important is probably the recency of engagement — what percentage of your list has opened or clicked in the last 30, 60, or 90 days. You can also look at your complaint rate, which is when someone hits 'report spam.' A complaint rate above one percent is a serious warning sign. And you can look at your bounce rate, especially hard bounces, which indicate a stale list. Luna: And I guess you should also track your list growth rate versus churn rate. If you're adding new subscribers faster than they're going cold, your list temperature is probably staying healthy. Lucas: Right. But there's also a more proactive way to manage temperature: your sending cadence. If you're sending too often, you might be annoying people and driving them to mark spam. If you're sending too rarely, you're letting the list cool down. Finding that sweet spot is key. For most weekly newsletters, one email per week is a good baseline. But it depends on your audience and the value you provide. Luna: So what's the takeaway for our listeners? I think it's that they should be checking their list temperature regularly, not just their subscriber count. Lucas: Absolutely. I'd suggest doing a temperature check at least once a quarter. Look at your engagement metrics, segment your list, and run a re-engagement campaign for anyone who's gone quiet for more than 60 days. And if they don't respond, let them go. It's better to have a smaller, hotter list than a big, cold one. Luna: And that's a lesson that applies to any business, whether you're a solo creator or a large enterprise. Email is still one of the most effective channels, but only if you treat your list like a living thing that needs nurturing. Lucas: Exactly. So, next time you're looking at your dashboard, don't just stare at the total number of subscribers. Ask yourself: how hot is this list? Because that's what's actually driving your results. Luna: And on that note, I think we've got a good framework for our listeners to take action. Thanks for being here, and we'll see you next time.