Latest / The Newsletter Podcast with Fexingo: Substack, Beehiiv, and Email Newsletter Business / How Newsletters Use Topic Clusters to Grow Subscriber Count
Transcript
- Lucas: So imagine you're writing a newsletter about personal finance, and you publish a single post that goes viral — you get three thousand new subscribers overnight. Feels great. But then what? You write another post, and maybe it gets a fraction of the traction. The spike fades. That's the trap a lot of creators fall into. Luna: Right, the viral spike is real but it's hard to replicate. So what's the alternative? Lucas: Topic clusters. Instead of hoping each post hits, you build a web of content around a single core topic. Think of it like a hub — a pillar page that covers the topic broadly — and then spokes, which are deeper dives on specific subtopics. They all link to each other. Google sees that interconnectedness and starts ranking your content higher for related searches. But more importantly, a reader who finds one piece is likely to click through to another, and another, and eventually subscribe. Luna: So it's not about one hit, it's about becoming the go-to resource for a specific niche. Who's doing this well? Lucas: I've been following a creator named James Clear — no, not that James Clear. This is James Routledge, who writes a newsletter called 'Remote Work Life.' He started on Substack in early 2025 with about 2,000 subscribers from a previous project. Ten months later, he's at 12,000. And when I looked at his strategy, it's textbook topic clusters. Luna: What's the core cluster? Lucas: Remote work productivity. His pillar page is something like 'The Ultimate Guide to Remote Work Productivity,' which is a long-form post with sections on time management, communication tools, setting boundaries, and so on. Then he has spokes: one post on 'Best Async Communication Tools for Remote Teams,' another on 'How to Avoid Burnout When Working From Home,' another on 'Morning Routines of Remote Workers.' Each spoke links back to the pillar, and the pillar links out to the spokes. Plus, they're all tagged and categorized on his Substack. Luna: So the reader who finds the 'Async Communication' post via a Google search might then click through to the pillar guide, and from there to the burnout post. That's three page views, and by then they're probably thinking about subscribing. Lucas: Exactly. And the SEO benefit compounds. Google's algorithm has something called 'topical authority.' If you consistently publish content on one topic and link it well, the search engine starts to trust you as an expert in that area. Your pages rank higher not just for the specific terms but for related long-tail queries. Routledge told me his organic search traffic grew from basically zero to forty percent of his total website visits within six months. Luna: Forty percent from search is huge for a newsletter. Most Substack growth comes from social media or word of mouth. So how did he pick the right topic? I imagine not every niche works for clusters. Lucas: He was already writing about remote work, but he decided to double down on productivity because he saw that his posts with productivity tips consistently got the highest open rates — around fifty-five percent compared to his average of forty-two. So he looked at his own data. Then he did some keyword research using free tools like Google's Keyword Planner to see what people were actually searching for. 'Remote work productivity tips' had decent volume but not insane competition. That sweet spot is key. Luna: So you need a topic that's broad enough to have search demand but narrow enough that you can realistically cover it comprehensively. What about the actual writing process? How many posts do you need to build a cluster? Lucas: Routledge started with the pillar post, which took him about three weeks to write and edit. Then he committed to publishing one spoke per week for the next eight weeks. So nine posts total over about two and a half months. He saw the first meaningful uptick in organic traffic after the fourth spoke went live — not immediately. Patience is part of the strategy. Luna: That's a significant upfront investment. I imagine many creators get scared off by the time commitment, especially if they're used to publishing shorter, more frequent posts. Lucas: True. But the payoff is more durable. One-off viral posts decay in traffic quickly — usually within weeks. A well-structured cluster can keep bringing in subscribers months later. Routledge told me that his pillar post from February 2025 still generates about two hundred new subscribers per month as of May 2026. Luna: That's a great example of an asset that keeps working. So how does this translate to platforms like Beehiiv, which is more focused on growth tools? Is the strategy different? Lucas: Beehiiv has built-in features that make clustering easier — like automated internal linking suggestions and a 'related posts' widget. You can also create a 'best of' page that functions as a dynamic hub. But the core principle is the same. I actually talked to a Beehiiv creator named Sarah Chen who runs a newsletter called 'Sustainable Fashion Weekly.' She used topic clusters to grow from 800 to 5,000 subscribers in about seven months. Luna: What was her cluster? Lucas: Sustainable fabric alternatives. Her pillar was 'A Complete Guide to Eco-Friendly Fabrics,' and then she did spokes on organic cotton, hemp, Tencel, recycled polyester, and so on. Each spoke included a call to action to download a free fabric comparison checklist — that lead magnet helped convert readers into subscribers. She told me that her pillar page has a conversion rate of about eight percent, which is double her site average. Luna: So the pillar page becomes not just a traffic magnet but a conversion engine. That makes sense — if someone reads a comprehensive guide, they're more likely to trust you and hand over their email. Lucas: Right. And the clusters don't have to be static. You can update the pillar periodically as new information emerges. Google rewards freshness. Routledge, for example, updates his remote work productivity guide every quarter with new tool recommendations and statistics. That signals to Google that the content is current, which helps maintain rankings. Luna: Let's talk about the internal linking structure specifically. What's the right way to link between pillar and spokes? Lucas: Both directions. The pillar should have a table of contents at the top, and each section should link to the relevant spoke for more detail. Then each spoke should have a contextual link back to the pillar — like 'for a broader overview, check out our complete guide.' Also, spokes should link to each other where relevant. For instance, the 'async communication tools' post might link to the 'avoiding burnout' post because using too many tools can lead to fatigue. That cross-linking builds a semantic web. Luna: What about anchor text? Should you use exact match keywords? Lucas: You can, but it's better to be natural. Google's algorithms are sophisticated enough to understand context. So instead of always linking with 'remote work productivity guide,' you might say 'our comprehensive guide to staying productive while working remotely.' Variety is good. And don't overdo it — one or two relevant links per post is plenty. Luna: One thing I'm wondering: does this work for newsletters that aren't purely educational? Like if you're doing a curated newsletter that aggregates news, can you still use clusters? Lucas: Absolutely. You could build a cluster around a recurring theme. For example, if your newsletter covers tech news, you might have a pillar on 'AI in Healthcare' and then spokes on specific topics like 'AI Diagnostics,' 'AI Drug Discovery,' and 'AI Ethics in Medicine.' Each issue that touches on AI in healthcare could link back to that pillar. Over time, you become a go-to source for that specific intersection. Luna: So it's about identifying the thread in your content and weaving it into a coherent tapestry. I think a lot of creators worry that they'll run out of things to say if they focus too narrowly, but clusters actually help generate ideas — each spoke reveals new angles. Lucas: Exactly. And once you have a few clusters, you can start interlinking across clusters. Routledge now has three clusters: productivity, remote team management, and work-life balance. His productivity cluster links to the team management cluster where there's overlap. That creates a site-wide authority that benefits all his content. Luna: Are there any metrics you'd recommend tracking to see if the cluster strategy is working? Lucas: I'd watch three things. One: organic traffic to the pillar page — if it's trending up, Google is rewarding you. Two: the number of new subscribers attributed to each spoke — you can use UTM parameters to track that. Three: the average session duration on your site — if people are clicking through multiple posts, your cluster is engaging. Routledge saw his average session go from 1 minute 30 seconds to 3 minutes 45 seconds over the first three months of the cluster strategy. Luna: That's a clear signal that readers are finding value. So for anyone listening who's thinking about starting a cluster, what's the first step? Lucas: Audit your existing content. Look at your posts with the highest engagement — open rates, click-through rates, comments. Identify a theme that keeps appearing. Then brainstorm a list of at least ten subtopics under that theme. Pick one pillar topic that's broad enough to be evergreen but specific enough to rank. Then write that pillar first. Don't worry about perfection — you can update it later. Then commit to writing one spoke per week for two months. That's the minimum to start seeing results. Luna: If today was actually useful to you, the way these stay ad-free is listener support — buy me a coffee dot com slash fexingo. Just a small way to keep the conversation going. Lucas: Yeah, we really appreciate that. So to wrap up, I think the key takeaway is that topic clusters flip the script from chasing ephemeral spikes to building a lasting asset. It's more work upfront, but the compound returns are real. And as search engines get better at understanding content relationships, this strategy is only going to become more important. Luna: I've been thinking about trying this with my own newsletter. I write about urban gardening, and I could see a cluster around 'balcony gardening' working well. I might start this weekend. Lucas: Do it. And let us know how it goes — maybe we'll have you back to share your results in a few months.