Latest / The Email Marketing Podcast with Fexingo: Newsletters, Open Rates, and Subscriber Growth / Why Email Throttling Improves Subscriber Experience
Transcript
- Lucas: I want to talk about something that feels counterintuitive — sending fewer emails to your most engaged subscribers. Luna: That sounds almost backwards. Aren't they the ones who want to hear from you? Lucas: They are. But here's the thing — engagement isn't a binary. Just because someone opened your last three emails doesn't mean they want to hear from you every single day. There's a concept that's been gaining traction in the B2B space called email throttling, and it's not about rate-limiting for deliverability reasons. It's about deliberately capping how many emails a single subscriber receives in a given window, regardless of campaign schedules. Luna: So you're saying we should actively hold back marketing emails from people who are currently clicking? I can already feel the pushback from revenue teams. Lucas: Right, and that pushback is exactly why I want to dig into this. Let's use a concrete case. There's a mid-size B2B SaaS company — I'll call them CloudFlow Analytics — that was sending about twenty emails per subscriber per month. Their open rates hovered around 38 percent, click-through rates around 4.2 percent. Solid numbers for the industry. But they noticed something: the top decile of subscribers by engagement were actually churning at a higher rate than the next two deciles combined. Luna: So the people who opened everything were also the ones leaving fastest. That's a classic burnout signal. Lucas: Exactly. So they decided to throttle. They built a simple rule: any subscriber who opened or clicked an email within the past seven days would be capped at two sends per week. Everyone else, the less engaged cohort, would get the standard four to five per week, essentially a re-engagement cadence. They also added a daily cap — no more than one email per day, period. Subscribers could override this with a preference center toggle, but the default was throttle. Luna: What happened over, say, a three-month period? Lucas: Total send volume dropped by 22 percent. That's the number the revenue team hated. But here's what happened to the metrics. Open rates on the throttled segment went from 38 percent to 51 percent. Click-through rate jumped from 4.2 to 5.6 percent. And here's the kicker — overall list churn rate dropped by 18 percent. So they lost some immediate sends, but they gained stickier engagement and a healthier list. The dollar value per subscriber actually increased over the quarter because the people who stayed were more likely to convert. Luna: I can see why that works. You're essentially protecting your best subscribers from themselves — from the fatigue that makes them eventually tune out or unsubscribe. Lucas: That's exactly the framing. And it's backed by some interesting data from the email service providers. Campaign Monitor and Mailchimp have both published benchmarks showing that brands sending three to five emails per week see the highest long-term subscriber retention. Once you cross the threshold of six or more per week, unsubscribes start climbing faster than engagement gains. But most brands don't throttle — they send every campaign to their entire active list. Luna: The fear is always opportunity cost. 'If I don't send this offer to my best people, I'm leaving money on the table.' But the data suggests the opposite — that throttling actually preserves the lifetime value of the subscriber. Lucas: And that's the tension. Marketing teams are measured on short-term metrics like campaign revenue or click volume. So throttling feels like you're deliberately lowering your numbers. But if you zoom out to a six-month or twelve-month view, the throttled list almost always outperforms the non-throttled one because you're keeping more people active. Luna: I'd love to talk about the implementation side. How do you actually set up throttling without making your email platform or your team crazy? Lucas: There are a few technical approaches. The simplest is to use a field in your CRM or email service provider that tracks 'emails sent in the last X days' and then use a conditional suppression rule. Most major platforms like HubSpot, Marketo, or Klaviyo have native ways to do this. You create a smart list or segment of subscribers who have received, say, more than two emails in the past seven days, and then exclude them from any campaign until the window resets. Luna: So it's basically a rolling cap. You could even do it per type of email, I imagine. Maybe you let transactional emails through, but throttle promotional ones. Lucas: Exactly. And that's actually a best practice — never throttle transactional emails like password resets or purchase confirmations. Those are expected and have high relevance. The throttling should apply to marketing emails — newsletters, offers, product updates, event invites. A lot of brands also differentiate by content type. A weekly newsletter might be exempt from the cap but daily promotional emails are not. Luna: What about the subscriber who genuinely wants to hear from you every day? You mentioned a preference center toggle. That seems critical — you don't want to force people to receive less if they've explicitly opted for more. Lucas: Absolutely. Give them a way to opt into a higher frequency. But the default should be the throttled version. Most people won't change the default, and that's fine. The ones who do are your superfans, and they'll self-identify. The key insight is that you don't lose them — they just get the email on their terms. And if they do opt for more, you can monitor their engagement separately and if you see fatigue signs, you can have a system that nudges them back to the standard cadence. Luna: This is really practical. I'm thinking about how a brand could test this. Maybe start with a random subset of their list, say ten percent, and throttle them for a month. Compare the throttled group to the control group on metrics like unsubscribes, open rates, and click-throughs. Lucas: That's exactly what CloudFlow Analytics did. They ran a ninety-day A/B test with a fifty-fifty split of their high-engagement segment. The throttled group saw a 31 percent reduction in unsubscribes and a 9 percent increase in conversion rate on their primary call to action. The control group, which got the normal cadence of almost daily emails, actually had a higher click volume but lower per-email efficiency. So the throttled group was more valuable per send. Luna: And those numbers are from a B2B company. I bet B2C e-commerce sees similar patterns. I know some retail brands send multiple emails a day during promotions, and that's where throttling could really protect the list. Lucas: Totally. In fact, there's a well-known case from a fashion retailer that used to send up to ten emails per week during holiday season. They throttled high-engagement subscribers to three per week and saw a 22 percent increase in revenue per subscriber over the quarter — because those subscribers were less fatigued and more likely to click when they did receive something. Luna: I think the biggest takeaway here is that more is not better. The instinct to fill every slot in a content calendar with an email to the whole list is hard to break, but the data is pretty clear. Lucas: And look, if you're listening and you're thinking about implementing this, start small. Pick one segment — maybe your 'high open rate but low click' group — and apply a weekly cap. Measure for thirty days. The results will probably surprise you. Luna: You know, conversations like this remind me why listener support matters for keeping the show ad-free. If these practical frameworks have helped you tweak your email strategy even a little, consider supporting the show at buy me a coffee dot com slash fexingo. It helps us keep digging into these specifics without any sponsor pressure. Lucas: Yeah, completely agree. No pressure, but if you've gotten value from episodes like this one, that link is a simple way to keep the conversation going. Now, back to throttling — I want to talk about one common mistake people make when they first implement this. Luna: What's that? Lucas: They apply the cap too rigidly. For example, some brands set a hard limit of two emails per week for everyone, regardless of engagement level. That's not throttling — that's just reducing frequency. The real power of throttling is that it's dynamic. It should respond to the subscriber's recent behavior. If someone hasn't opened an email in thirty days, you should actually increase frequency slightly to re-engage them — but with content specifically designed to win them back. Luna: So throttling is really about finding the optimal frequency for each subscriber in real time. It's not a one-size-fits-all cap. Lucas: Exactly. And that's where algorithmic pacing comes in. Some advanced ESPs now offer machine learning models that predict the optimal send time and frequency for each subscriber. But even a simple rules-based system — like 'if opens in last 7 days, cap at 2; if no opens in 30 days, cap at 4' — can outperform a flat schedule. The key is to treat frequency as a variable you optimize, not a constant. Luna: I love that framing. One last question — what about the impact on deliverability? Does throttling help with that too? Lucas: Indirectly, yes. When you send fewer emails to people who are less likely to engage, you reduce spam complaints and bounces. Internet service providers like Gmail and Outlook pay close attention to engagement signals. If a subscriber receives an email but doesn't open it, that's a negative signal. Over time, a high volume of unopened emails can hurt your sender reputation. Throttling helps keep your engagement metrics high, which in turn protects your deliverability for the emails you do send. Luna: So it's a virtuous cycle — better engagement leads to better deliverability, which leads to more emails landing in inboxes, which leads to more engagement. Lucas: Exactly. And that's why I think throttling is one of the most underused strategies in email marketing right now. It's not flashy, but it works. Luna: Alright, I think we've given our listeners plenty to test. Next time, I want to talk about something we've touched on a few times — how to design preference centers that actually get used. Lucas: That's a great one. We'll see you next episode.