27
editions of Growth Curve read, April 16 to October 8, 2026
Spacebar wrote 27 issues about growing a newsletter. Ten of the lessons hold up for a firm like yours.
Growth Curve is Spacebar's weekly newsletter about how media businesses grew. We read all 27 editions published between April 16 and October 8, 2026, and kept the ten growth lessons that survive contact with a consultancy's economics.
78%
of Lenny's new subscribers came from other newsletters' recommendations (October 2022)
4.6M
readers at 1440, which waited to pay for growth until its open rate reached 45%
30,000
active readers recruiting for theSkimm at its referral program's height
Every Thursday, David Campbell takes one media business apart for Growth Curve: how 1440 reached 4.6 million readers, how Lenny Rachitsky built the biggest product newsletter in the world with no full-time staff, how The Hustle ended up inside HubSpot. The stories are good, and the archive is open.
Most of these companies had a head start you don't have, like venture money, a famous founder or millions of consumer readers. That's fine. Nobody is asking you to become Morning Brew.
The useful question is what each story teaches a firm that sells its expertise, and that translation is the whole point of this piece. We ranked ten lessons in the order we'd act on them.
1,000
subscribers, the wall Growth Curve says most B2B newsletters struggle to get past
Give discovery a recurring job.
Growth Curve's April 16 editorial argues that most B2B newsletters plateau once the founder's network has signed up. Its fix pairs articles people find in search with LinkedIn posts that point back to a deeper asset.
Your first few hundred subscribers come from people who already know you: clients, past colleagues and the partner who sends you referrals. Then the list stops growing, and most firms blame the writing. The writing is usually fine. Nothing new is pointing people at it.
Give every issue a second life. Turn its best idea into a public article someone could find by searching for the problem, and into two LinkedIn posts that end with a reason to subscribe. Count where new readers came from, and keep the routes that bring the right people.
$1
about what Tangle paid Meta for each new email subscriber in early 2026
Count the readers who stay, not the ones who sign up.
Growth Curve's Tangle profile (August 20) reports that Tangle's $1 Meta subscribers converted to paid more slowly than readers from other channels. Its Hell Gate profile (October 1) describes a 99-cent month with a free hat that drew subscribers who canceled at the regular price.
You don't sell subscriptions, so translate the test. The reader you want replies, comes back, forwards an issue to a colleague, and one day asks what working with you looks like.
Judge every source of new readers after the promotion ends. Check each group at 30, 60 and 90 days. A giveaway that adds 500 names and no conversations makes your list longer and your open rate lower.
45%
the open rate 1440 wanted (45 to 50%) before it would pay for a single reader
Prove people read it before you pay to grow it.
The 1440 profile (July 2) reports that co-founder Tim Huelskamp refused to spend on paid acquisition until the newsletter held a 45 to 50% open rate and clearly kept its readers. 1440 now reaches about 4.6 million people.
Paid growth multiplies whatever you already have. If people open and answer issue eight, an ad budget brings you more of those people. If they don't, it brings you more people who don't.
Send several issues to the list you have before you spend a dollar finding new names, and set any budget by what a retained reader is worth to you. 1440's threshold belongs to a consumer daily, so don't treat it as your pass mark. Borrow the order of operations instead.
78%
of Lenny's new subscribers came from other newsletters' recommendations in October 2022
Let someone your readers already trust vouch for you.
Growth Curve's Lenny profile (August 13) reports that in October 2022, 78% of Lenny Rachitsky's new subscribers came from other newsletters that recommended him.
A recommendation carries trust you haven't earned yet. The reader already believes the person sending it, and that belief transfers to you for one click.
Find three people who write for the readers you want, like a complementary firm or a consultant who serves the same buyers from another angle. Ask each to recommend one specific issue that solves a problem their readers have, and return the favor. Lenny's 78% is one writer's number from October 2022, so treat it as a story, not a target. The mechanism is what travels.
30,000
active Skimm'bassadors at the height of theSkimm's referral program
Make referring feel like helping someone.
Growth Curve's theSkimm profile (June 4) reports that theSkimm gave loyal readers referral links and small, social rewards, including the title Skimm'bassador. At its height the network passed 30,000 active members and became the main growth engine.
The rewards were small. The identity did the work. Your version starts smaller and more specific. End an issue by naming the person who needs it: "If you know an operations lead who's about to renegotiate a vendor contract, send them this."
A forward works when it feels like helping a colleague, not doing you a favor.
If you test rewards later, keep them useful to the people you serve. A prize that appeals to everybody brings you everybody.
8
professional newsletters Morning Brew built from readers already on its consumer list
Your list already holds the segments you want.
The Morning Brew profile (July 9) reports that Morning Brew found the finance people, marketers and technologists inside its 4 million general readers and moved them into eight newsletters built for their work.
You don't need eight newsletters. You probably need one good question. Ask new subscribers what they do or what they are working on, once, when they sign up, and you'll learn which group dominates your list.
When one group is big enough, give it a recurring section or an occasional issue of its own. Start a second publication only when the demand is obvious.
07
Stratechery, a one-person subscription business
Give away an issue worth forwarding.
The Stratechery profile (June 25) reports that Ben Thompson treated free writing as the marketing and paid writing as the product, and readers forwarded the free pieces and argued about them.
Your paid product is the engagement. The free issue plays the role Thompson's free article plays, so it has to deliver on its own.
Solve one real problem in every issue, completely, so a reader gets the benefit without booking a call. Put the offer of help at the bottom. The reader who got something useful for free is the one who calls when the problem outgrows them.
Holding back the good part to force a meeting does the opposite. Nobody forwards a teaser.
300
words, the usual ceiling on an Axios story, under recurring labels like Why it matters
A recognizable format makes you easier to recommend.
The Axios profile (July 23) reports that Axios usually kept stories under 300 words with recurring labels and trademarked the approach as Smart Brevity. The Tangle profile (August 20) describes an email that follows the same order every day.
A reader who can describe your newsletter in one sentence can recommend it in one sentence. A steady format is what makes that sentence possible.
Decide the question every issue answers and the order it answers it in. Maybe that's one market change, what it means for your clients and one thing to do this week. A steady spine also makes the newsletter faster to produce, which matters when the person writing it also runs the firm.
$20.3M
what HubSpot's filings say it paid for The Hustle (Axios had first estimated $27 million)
Build the list around people who might hire you.
The Hustle profile (August 6) reports that The Hustle's readers matched HubSpot's target customer almost exactly. The Industry Dive profile (September 17) shows the same logic in narrow professional markets.
HubSpot paid for fit, and fit is the one thing a service firm can build on purpose. Write down who might hire you, rehire you or refer you, then list the decisions they make every quarter that your expertise can improve. Those decisions are your editorial calendar.
A thousand readers who match that description are worth more to you than fifty thousand who don't.
13,000
subscribers to Strikegeist, The Ankler's free newsletter during the 2023 Hollywood strikes
A timely problem brings in readers you couldn't reach before.
The Ankler profile (October 8) reports that Strikegeist, a free newsletter launched during the 2023 strikes, reached about 13,000 subscribers and brought thousands of writers and actors into its readership.
Every industry gets its strike moment: a regulation change, a platform shift, a pricing shake-up every client is asking about. That's when people go looking for someone who understands it.
Write a short series on the problem while it's live. The topic has to connect to what you publish the rest of the year, or the new readers leave when the news cycle does.
Run three of these this month.
You already have a list: past clients, open proposals and referral partners.
Add one question to your signup form. End your next issue by naming the colleague who needs it. Find one writer whose readers overlap with yours and offer a recommendation swap built around a specific issue.
Count replies and forwards before you count subscribers. If writing the issue every two weeks is the part that keeps slipping, that's the part we take off your desk.
Growth isn't a channel you buy. It's what happens when you are worth hearing from.
We write newsletters that keep businesses talking with the people they serve. If this piece connected with something you've been putting off, tell us what you sell and we'll tell you honestly if a newsletter will help. Start or fix yours
Source: Growth Curve, Spacebar's newsletter, written by David Campbell. We read the 27 editions published between April 16 and October 8, 2026, at growthcurvenewsletter.com, and rechecked every edition we cite on October 23, 2026. The case figures are Growth Curve's reporting about the companies named, not audited results. None of this is a WTF Growth client result.