Latest / The Email Marketing Podcast with Fexingo: Newsletters, Open Rates, and Subscriber Growth / Why Email List Appends Are a Disaster
Transcript
- Lucas: So there is a move in email marketing that almost never works, and yet I see people try it every quarter. List appends — buying or renting a batch of email addresses and adding them to your existing subscriber base. Luna: Yeah, and I think the temptation is obvious. You want a bigger list fast. But the inbox providers have gotten so good at detecting that behavior. Lucas: Exactly. So let's talk about why it backfires, and what to do instead. And I'll start with a concrete case. There was a mid-size e-commerce brand — apparel, let's call them 'Thread & Needle' — that did a list append in late 2024. They bought about 50,000 addresses from a third-party broker, merged them into their main list, and sent a campaign. Luna: And what happened? Lucas: Their open rate dropped from around 28 percent to under 12 percent within two weeks. Their click-through rate basically flatlined. But the worst part was their deliverability. Gmail and Outlook started routing their emails to spam — not just for the appended addresses, but for their entire list. Their sender reputation took a hit that took six months to recover. Luna: That's the part people don't anticipate. It's not just that the new addresses bounce or go to spam. It poisons the well for your existing subscribers. Lucas: Right. And the mechanism is straightforward. Inbox providers, especially Gmail and Microsoft, track engagement at the domain level. When you send to a batch of addresses that have never interacted with you — that have no prior engagement, no consent — those are flagged as unknown or unengaged. If a high percentage of your sends go to those addresses, the algorithms start treating your entire sending stream as suspicious. Luna: So it's a signal problem. Your sending patterns change abruptly, and the algorithm sees that as a red flag. Lucas: Precisely. And it's not just algorithmic. There's also the legal angle. In Europe, under GDPR, you need explicit consent to send marketing emails. Buying a list and emailing those people without their permission is a violation. Fines can be up to four percent of global revenue. In the US, can spam requires a clear opt-out mechanism, but it doesn't forbid cold emailing entirely. However, the FTC has been cracking down on deceptive practices. Luna: And let's not forget that many of those appended addresses are stale or belong to people who never signed up. They're likely to mark your email as spam, which hurts reputation even more. Lucas: Exactly. So the question becomes: if list appends are so risky, why do marketers still do them? I think part of it is pressure to show list growth. A manager says 'we need to add 100,000 subscribers this quarter,' and buying a list seems like the fastest shortcut. Luna: But it's a shortcut to a worse place. So what's the better approach? Let's talk about double opt-in. Lucas: Yeah, double opt-in is the gold standard. Someone enters their email on your site, you send them a confirmation email with a link they have to click. It adds friction, yes. You might lose 20 to 30 percent of signups at that step. But the people who do confirm are highly engaged. They've proven they want to hear from you. Luna: And that engagement signal is gold for deliverability. Gmail sees that confirmation click and knows it's a real person who opted in. Lucas: Right. And you can also use a preference center. Let people choose what they want to receive — daily emails, weekly digests, product updates only. That further increases engagement because you're sending relevant content. Luna: And if you absolutely need to add cold contacts — say, you're doing a partnership with another brand — you should use a co-registration approach where the new subscriber explicitly opts in to your list as part of the signup process. Lucas: That's a good middle ground. Another tactic is to run a re-engagement campaign for old subscribers before you even think about adding new ones. Often, you have a list of people who haven't opened in six months. Win them back or prune them. That cleans your reputation. Luna: Yeah, because a clean list of engaged subscribers is worth more than a bloated list of zombies. And by the way, if you're finding these marketing conversations useful — if something we've said has helped you rethink your email strategy — we keep this show ad-free thanks to listeners who support us at buy me a coffee dot com slash fexingo. No pressure, just a heads up. Lucas: Appreciate that. And it really does help us keep the lights on. So back to the main thread: let's talk about what happens if you've already done a list append and you're dealing with the fallout. Luna: Yeah, how do you fix it? Lucas: First, immediately stop sending to the appended addresses. Segment them out. Then run a confirmation campaign — send those addresses a 'did you sign up?' email with a link to confirm. Anyone who doesn't confirm gets removed permanently. Luna: And while you're doing that, you need to warm up your sending domain again. That means sending small volumes to your most engaged subscribers, gradually increasing as engagement metrics improve. Lucas: Exactly. You might also need to pause sends for a few days to let the reputation cool down. And check your blacklists — there are tools like MXToolbox or Spamhaus that let you see if your domain has been listed. Luna: Another thing: if you have a dedicated IP address, you might need to contact your email service provider to request a reputation reset. Some ESPs can help with that. Lucas: Right. But ideally, you never get to that point. The takeaway is simple: organic list growth through double opt-in, preference centers, and content upgrades beats any shortcut. Every time. Luna: And if you're tempted by a list append, just think about Thread & Needle. Their recovery took six months. That's a lot of lost revenue and wasted effort. Lucas: Absolutely. And we have not even touched on the fact that many appended addresses are actually spam traps — addresses set up by ISPs specifically to catch spammers. If you hit one of those, your reputation takes a nosedive instantly. Luna: That's a nightmare scenario. So let's summarize: don't buy lists, use double opt-in, and clean your list regularly. That's the recipe for sustainable email marketing in 2026. Lucas: And with that, we will wrap up. Next episode we are diving into how to use AI to personalize subject lines without sounding robotic. See you then. Luna: See you.