Latest / The Email Marketing Podcast with Fexingo: Newsletters, Open Rates, and Subscriber Growth / How Email List Honeypots Catch Unengaged Subscribers
Transcript
- Lucas: So let's talk about something that sounds almost like spycraft but is actually just smart email list management: honeypots. Luna: Honeypots. Like baiting people, or in this case, baiting bots and bad actors? Lucas: Exactly. In cybersecurity, a honeypot is a decoy system meant to lure attackers. In email marketing, it's a decoy email address you plant in your signup flow or your website, one that no real human would ever legitimately submit. Luna: So if someone — or something — grabs that address and tries to use it, you know they're not a genuine subscriber. Lucas: Right. And that's incredibly useful because a lot of the damage to your sender reputation comes from sending to addresses that were harvested by bots, or that were added via fake signups. Those contacts don't engage, they bounce, they mark you as spam. Honeypots let you catch them early. Luna: I can see how that would be especially valuable for B2B companies, where lead quality matters a ton. Do you have a specific example? Lucas: Yeah, there's a mid-size B2B SaaS company — I'll call them CloudAnalytics — that started using honeypots last year. They had a list of about 150,000 subscribers, but their inbox placement rate had dropped to 84 percent. They were seeing way too many soft bounces and spam complaints. Luna: Ouch. 84 percent is rough. Industry average is usually above 95. Lucas: Exactly. So they planted three honeypot addresses. One in the footer of their blog, hidden in the HTML but invisible to users. One in their free trial signup form as a hidden field. And one in a low-traffic careers page. Over six months, those honeypots caught about 2,300 submissions. Luna: Wow. So that's 2,300 addresses they know are bad. What did they do with them? Lucas: They didn't just delete them. They actually tracked the IP addresses and user agents from those submissions to build a blocklist. Then they removed any subscriber that shared similar patterns — same IP range, same browser fingerprinting signals. They cleaned out about 4,000 suspect contacts. Luna: And the result? Lucas: Inbox placement went from 84 percent to 96 percent over the next six months. Open rates on their core campaigns jumped from 18 percent to 26 percent. And their spam complaint rate dropped below 0.05 percent. Luna: That's a huge improvement just from removing bad contacts. But I imagine the key is that they didn't just blindly delete — they used the data to proactively block similar threats. Lucas: Absolutely. And this is where it ties into something we talk about a lot on this show: the idea that a smaller, cleaner list is more valuable than a big, messy one. Honeypots are one of the most surgical ways to achieve that cleanliness. Luna: Speaking of valuable, we should mention that this show stays ad-free because listeners like you support it directly. If these marketing conversations have sparked something you've actually used in your own work, you can help keep it independent at buy me a coffee dot com slash fexingo. Lucas: Yeah, it's a small gesture that makes a big difference for us. And it means we never have to compromise on topics or chase sponsor-friendly angles. Luna: Exactly. Now back to honeypots — what about the risk of accidentally trapping a real subscriber? That seems like a potential downside. Lucas: It's a real concern. If you're not careful, you could flag a legitimate user who fat-fingered an email address that happens to be your honeypot. That's why best practice is to use addresses that are obviously fake — like 'noreply@yourdomain.com' or 'spam@yourdomain.com' — and to never, ever email them. Luna: So you're not sending anything to the honeypot, you're just monitoring if someone submits it. Lucas: Correct. The honeypot address itself should never receive a marketing email. If it does, you've defeated the purpose. You want it to be a silent canary in the coal mine. Luna: Got it. So what about the implementation? Is this something a small e-commerce brand could do, or does it require a lot of engineering? Lucas: It's actually pretty straightforward. Most email service providers like Mailchimp or Klaviyo allow you to create custom fields or tags. You can add a hidden form field that's not visible to the user, and then set up a rule that flags any submission where that field contains a value. Or you can use a tool like Zapier to log submissions to a honeypot address into a spreadsheet. Luna: And then you manually review and remove? Lucas: You can automate it. Once you're confident the honeypot is working, you can set up a webhook that automatically suppresses any subscriber who submitted that address. The key is to test thoroughly first. Luna: Let's talk about the types of honeypots. You mentioned hidden form fields and blog footer links. Are there others? Lucas: Yeah, there's a classic one called the 'email trap' that's been around for decades. It's an email address that was once valid but has been abandoned and repurposed by anti-spam organizations. If you send to it, you get blacklisted. But that's more defensive. The proactive honeypot is the one you plant yourself. Luna: So a self-planted honeypot is more about catching bad actors during signup, not after you've already sent. Lucas: Exactly. And there's another variant: using a honeypot in your preference center. If someone changes their email address to your honeypot, that's a strong signal they're trying to game your system or that their account was compromised. Luna: That's clever. I've also heard of companies using honeypots to detect competitor scraping of their email lists. Lucas: Right. You can seed unique honeypot addresses into different parts of your site. If a competitor scrapes your blog and sends a campaign to that address, you know exactly where the leak is. Luna: So it doubles as a kind of leak detection system. That's a nice bonus. Lucas: It is. And it brings us back to the core principle: list hygiene isn't just about removing bad contacts. It's about understanding how they got there in the first place. Honeypots give you that insight. Luna: Alright, so let's say someone's convinced. What's the first step they should take tomorrow? Lucas: Create one honeypot address. Something simple like 'test@yourdomain.com' or 'verify@yourdomain.com'. Add it as a hidden field in your primary signup form. Then set up a rule in your ESP: if that field is submitted, tag the record as 'honeypot caught'. After a week, review how many you've caught. If it's more than a handful, you've got a bot problem worth addressing. Luna: And if it's zero? Lucas: Then you're probably fine, but you might still want to add more honeypots in other locations. It's low cost, low risk, and the upside is real. The CloudAnalytics case shows that even a mature list can have hidden rot. Luna: I like that. It's a concrete, actionable tactic that doesn't require a big budget. And it directly protects your sender reputation, which is everything in email. Lucas: Exactly. One of those rare moves that pays for itself many times over. And it's surprisingly underused. Most marketers focus on re-engagement campaigns for unengaged subscribers, but honeypots catch the ones who were never engaged in the first place. Luna: Which is a fundamentally different problem. Re-engagement is for people who once cared. Honeypots are for people who never did. Lucas: Right. And that distinction matters because the remedy is different. For the never-engaged, you don't want to waste resources trying to win them back. You want them gone. Luna: So if listeners take one thing from this episode, maybe it's that cleaning your list isn't just about removing the inactive — it's about removing the invalid. Lucas: Well said. And honeypots are the most direct way to identify the invalid. They're not a silver bullet, but they're a damn good starting point.