Latest / The Newsletter Podcast with Fexingo: Substack, Beehiiv, and Email Newsletter Business / How One Newsletter Turned Reader Replies Into a Profitable Product
Transcript
- Lucas: So there's a moment in every newsletter writer's week that feels like a chore, and I think it's the moment that's actually hiding a ton of revenue. I'm talking about reading the replies to your email. Luna: You mean the ones that aren't just 'unsubscribe' or 'great post'? Lucas: Exactly. The real replies. The ones where a reader actually takes two minutes to type out a question or a frustration. Most writers skim them, maybe paste one into a testimonial, and move on. But there's a newsletter I've been watching — it's a niche financial research letter, about 25,000 subscribers, not a name you'd know — and they turned a single reader reply into a paid research service that's now 30 percent of their revenue. Luna: Thirty percent from one email? What was the question? Lucas: So the writer covers small-cap biotech — very specific, very jargon-heavy. And one morning, a subscriber — a retail investor, not a professional — replied to the morning brief with something like, 'I get all the clinical trial news, but can you just tell me what actually matters for the stock price?' And that's it. That's the whole email. But the writer read it and realized that's the exact gap between what he was writing and what his audience actually needed. Luna: So they didn't just answer the question — they built a product around it. Lucas: Right. Within a month they launched a premium tier called, and I love this, 'The Bottom Line' — it's a one-page weekly that strips every trial result down to 'stock impact: high, medium, or low, and why.' Priced at 30 dollars a month. And the kicker is, they validated the demand first by just running a poll in the next few issues — 'would you pay for this?' — and 18 percent of readers said yes. That's a huge signal for a paid product. Luna: Eighteen percent is massive. But I feel like most readers don't reply with that kind of clarity. How do you separate the signal from the noise? Lucas: That's the real skill. And honestly, most of the signal isn't in the question itself — it's in the pattern of questions across a few weeks. If you get three or four variations of the same 'just tell me what matters' request, that's not a one-off, that's a market. Luna: So you're looking for repetition. Not just a single good idea. Lucas: Exactly. And the repetition can come from different angles — one person asks for a summary, another asks for a 'quick take,' a third says 'I don't have time for the full research report.' All three are asking for the same underlying thing: a faster path to the conclusion. That's your product. Luna: I've seen the opposite too, though — where a writer gets a really specific request and builds exactly that, but the feature or product ends up being too narrow. How do you tell the difference? Lucas: Good question. The narrow request is usually about a single feature — 'can you add a glossary of terms?' That's a feature, not a product. The broader signal is about a job to be done — 'help me understand what matters' is a job. 'Add a glossary' is a feature. And the best newsletters I've seen don't just build the feature; they build a whole product around the job. Luna: So you're saying a feature request is actually a clue to a much bigger problem. Lucas: Yes, and that's exactly what another writer I follow did. This one's a Substack author covering metabolic health — think intermittent fasting, glucose monitors, that world. She got a reader email asking, 'Can you do a post on how to talk to your doctor about getting a CGM?' Just that. But she saw the pattern behind it: a bunch of her readers were hitting the same wall — they were convinced by the science but couldn't get their clinicians to take them seriously. So she built a whole paid course called 'The Patient's Playbook' — scripts for appointments, PDFs of the latest studies, a cheat sheet of what to say and what not to say. And that course is now her top product. Luna: That's a perfect example of reading the intent behind the words. The reader didn't ask for a course — they asked for help with a conversation. Lucas: Right. And the advice she gives to other writers is something I've been thinking about a lot: don't just read the replies, categorize them. She literally keeps a spreadsheet — every week she tags every substantive reply with the underlying need. Is it 'I need more detail'? Is it 'I need a simpler version'? Is it 'I need help convincing someone else'? After a month, the categories tell you where the demand is. Luna: A spreadsheet feels very unglamorous, but it's probably exactly what separates hobby newsletters from businesses. Lucas: It is, 100 percent. And the thing is, most writers already have the data — they just don't have a system for it. The replies are sitting there in the inbox, and they're literally free market research. But because we treat email replies as a chore, we miss the gold mine. Luna: What about the writers who get like, 50 replies a day? That's a lot of categorization. Do you automate it? Lucas: At that scale, you can use AI tools to help cluster replies, but honestly, for most newsletters, the volume isn't that high. Even at 50,000 subscribers, you might get 20 to 50 substantive replies a week. That's really a 30-minute task. And you can use a simple three-column table in a spreadsheet or even a Notion database. Luna: But doesn't this risk over-fitting your product to your most vocal readers? I mean, the people who reply are often the superfans, not the typical reader. Lucas: That's a fair challenge, and it's the right one. The vocal minority can lead you astray if you only listen to them. But here's the trick: when you see a pattern in replies, you don't just build the product — you validate it with a broader poll or a quick email survey. That's exactly what the biotech newsletter did. They saw the pattern, then they asked the whole list, and the poll told them the demand was real. Luna: So replies are the hypothesis, and a poll is the test. Lucas: Exactly. And that's what makes this approach so powerful — it's low-cost, it's fast, and it's genuinely customer-driven. You're not guessing what your audience wants; you're surfacing what they're already telling you. Luna: I have a friend who runs a marketing newsletter — she got a reply from someone asking for a 'cheat sheet of email subject line formulas.' She ignored it for weeks. Then she saw three more similar requests and finally made a PDF. She sold it for 19 dollars, and it's been a steady drip of passive income ever since. Lucas: That's a classic example. And it shows the range — it doesn't have to be a full-blown course or a premium tier. It can be a simple lead magnet, a paid guide, a template pack. The principle is the same: readers are telling you exactly what product they want to buy. You just have to listen. Luna: And I'd add that even the questions you can't answer are valuable. A while back, I heard a story about a newsletter writer who got a question she had no idea about. Instead of ignoring it, she researched it, wrote a mini-report, and that became one of her most-shared posts. It turned into a whole new content pillar. Lucas: That's a great point — a question you can't answer is a lead for future content. And that content, in turn, attracts more readers who have the same question. It's a virtuous cycle. Luna: But what if you're not getting many replies at all? Like, you send a newsletter and it's just crickets. How do you encourage more of that feedback? Lucas: You have to ask for it, explicitly. And I don't mean the generic 'reply to this email' — I mean a direct prompt at the end of a post: 'What's your biggest struggle with X right now?' Or even better, make it a specific question that's easy to answer: 'Reply with one word: what's your biggest challenge?' That lowers the barrier. You'll get a lot of one-word answers, but you'll also get some people who type a whole paragraph. Luna: So you're mining for that deeper reply, but you're giving people an easy way in. Lucas: Exactly. And once you start replying personally to those people — even just a 'thanks, this is really helpful' — you'll see that reply rate go up. You're building a relationship, and people are more likely to open up to someone they feel is listening. Luna: It's kind of a flywheel, isn't it? The more you listen, the more people want to talk, the more data you get, the better your products become. Lucas: That's the whole game. And I think that's why this angle — mining reader replies — is so underrated. It's not a one-time trick; it's a system you can run every week, forever. And it's the kind of thing that compounds. Luna: If today's episode gave you a concrete way to turn reader replies into your next product, that's exactly the kind of thing that keeps this podcast ad-free. If you found it useful, you can support the show at buy me a coffee dot com slash fexingo. It genuinely helps us keep these conversations coming. Lucas: And speaking of compounding — the best part is, this isn't a one-time strategy. Once you build a product from reader feedback, you can keep doing it. The biotech newsletter didn't stop at 'The Bottom Line.' They now have three paid tiers, and each one came from a different pattern they spotted in reader replies. Luna: So the first product validated the approach, and now it's a repeatable engine. Lucas: Right. And that's the real takeaway: your readers are already telling you what to build. The only question is whether you're listening. So this week, scroll through your inbox, look at the replies you've been ignoring, and see if there's a pattern. That's where your next product is hiding.