Latest / The Email Marketing Podcast with Fexingo: Newsletters, Open Rates, and Subscriber Growth / Why One Email Address Can Ruin Your Sender Reputation
Transcript
- Lucas: So here's a number that stopped me this week: according to data from Validity, roughly one in every two hundred email addresses on the average marketing list is a spam trap. Luna: One in two hundred. That sounds small — until you realise a list of fifty thousand subscribers has about two hundred fifty addresses that could get you blacklisted. Lucas: Exactly. And the thing about spam traps is they look like real addresses. They're not obvious. Mailbox providers — Gmail, Outlook, Yahoo — seed these addresses into the wild specifically to catch senders who aren't practicing good list hygiene. Luna: So we're talking about honeypots, essentially. Lucas: Right. There are two main types. The first is a pristine spam trap — an address that was never owned by a real person. It's created by the provider and placed on a website or in a public directory. If you're sending to it, you almost certainly scraped or bought that address. Luna: Which means you're not using permission-based marketing at all. Lucas: Correct. The second type — and this is the one that catches legitimate senders — is a recycled spam trap. This is an address that was once a real person's inbox, but the provider deactivated it after a period of inactivity, say six months or a year, and then repurposed it as a trap. Luna: So if someone unsubscribes implicitly — by just never opening — and you keep sending, you might eventually hit a recycled trap. Lucas: That's the danger. And the consequences are not theoretical. If you hit a single spam trap, your sender reputation takes an immediate hit. Major providers like Gmail use a scoring system — typically zero to one hundred — and anything below the mid-eighties starts routing your mail to spam folders or even blocking it entirely. Luna: And it's not just that one campaign. It's your entire sending domain for weeks. Lucas: Yes. So let me give you a concrete example. I talked to a marketing director at a mid-size e-commerce brand — about a hundred thousand subscribers — who purchased a third-party list of 'interested prospects' from a data broker. They sent one welcome campaign to that list. Their open rate, which had been running around 28 percent, dropped to 9 percent overnight. It took them three months of intensive list cleaning and warm-up sequences to get back to their baseline. Luna: And that's not counting the lost revenue from the emails that never reached customers. Lucas: Exactly. The direct cost of the purchased list was maybe a few hundred dollars. The indirect cost — lost sales, damaged reputation, time spent fixing it — was easily in the tens of thousands. Luna: So how do you avoid this? What's the practical checklist? Lucas: First and most important: never buy a list. I know it's tempting when you're trying to grow fast, but the data is clear — purchased lists have spam trap rates that are orders of magnitude higher than organic lists. Luna: And even if you're not buying, if you're growing organically, you still need to prune. Lucas: Right. So step two: implement a sunset policy. If a subscriber hasn't opened any email in six months, put them in a re-engagement sequence. If they don't respond to that, remove them from your active list. Don't just keep sending indefinitely. Luna: What about the re-engagement email itself? Does that risk hitting a trap? Lucas: It can, if the address has already been recycled. That's why you should use a separate sending domain or subdomain for re-engagement campaigns — so if you do hit a trap, it doesn't contaminate your primary domain. You can also check against known spam trap lists using third-party services like Return Path or 250ok. Luna: So there's a cost to that, but it's a fraction of what a reputation hit costs. Lucas: Absolutely. And step three: use confirmed opt-in — double opt-in — not just single opt-in. With single opt-in, someone can type any email address into your form, and it's added to your list immediately. With double opt-in, they have to click a confirmation link, which verifies the address is real and that the person actually wants your emails. Luna: It does lower your signup conversion rate — I've seen drops of ten to twenty percent. Lucas: It does. But the trade-off is a cleaner list, higher engagement, and a much lower risk of spam traps. And for most businesses, a smaller but more engaged list actually drives more revenue than a bigger list full of dead weight. Luna: I think that's the piece a lot of marketers miss — they optimise for list size instead of list health. Lucas: Exactly. If you have fifty thousand subscribers but only ten percent are opening, you're effectively paying to send to forty-five thousand people who don't care. And those forty-five thousand include potential spam traps. Luna: Speaking of paying — one thing that often gets overlooked is the cost of wasted sends on email service provider platforms. Many charge based on total list size, not active senders. Luna: Alright, so let's say someone's already hit a spam trap. What's the recovery playbook? Lucas: First, stop sending to the entire list immediately. Identify the trap address — your email service provider's bounce reports will usually flag it. Remove it, and any other suspicious addresses from the same source. Then, segment your list by engagement level. Only send to your most active segment — people who have opened in the last thirty days — for a couple of weeks. That rebuilds your reputation with the mailbox providers gradually. Luna: And you're essentially proving to Gmail that you're not a spammer by showing high engagement rates. Lucas: Right. Once your sender score recovers above, say, ninety, you can slowly reintroduce less engaged segments — but only those that have opened in the last three or six months. Anything older than that, you should sunset. Luna: There's a tool from Validity called Everest that gives you a daily sender score. I've been using it — it's eye-opening. Lucas: Good recommendation. And there's also Google's Postmaster Tools if you're sending a lot of mail to Gmail addresses. It'll show you your reputation, spam rate, and feedback loop data for free. Luna: You know, this whole conversation reminds me why I appreciate shows like this that go deep into the mechanics. A couple of dollars a month is genuinely what keeps these going — buy me a coffee dot com slash fexingo, if you've gotten something out of them. Lucas: Yeah, it really does make a difference. Keeps us independent and focused on the stuff that matters — like how not to get your emails blocked. Luna: Alright, so back to list health — one more thing I want to touch on is the role of engagement scoring over time. Lucas: Good. Because the mistake a lot of people make is they clean their list once and think they're done. But list hygiene is ongoing. Subscribers' habits change, addresses get recycled — you need to be constantly monitoring engagement metrics. Luna: What's the right cadence? Monthly? Quarterly? Lucas: I'd say at least quarterly for full list pruning. But you should also have automated triggers — if someone hasn't opened in ninety days, flag them for a re-engagement sequence. If they don't engage with that, remove them automatically. Luna: And you can set that up in most email service providers now. Lucas: Yes, Mailchimp, Klaviyo, HubSpot — they all have automation for this. The key is to actually turn it on. I still see plenty of accounts that have the feature but never configure it. Luna: It's one of those 'set it and forget it' things that pays for itself. Lucas: Exactly. Alright, to wrap up — the single most important takeaway: your sender reputation is your most valuable email asset. It takes months to build and one spam trap to damage. Protect it with double opt-in, regular pruning, and engagement-based sending. Luna: And if you ever feel tempted to buy a list, just remember that one-in-two-hundred number. Lucas: Right. Thanks for listening — we'll be back next week with another deep dive into the metrics that actually move your business.