How a Tech Newsletter Tested Whether a Subscription Business Could Survive Leaving Its Distribution Platform

In January, 2024, Casey Newton announced that Platformer, the tech newsletter he had built on Substack since October 2020, would migrate to Ghost, a nonprofit open-source publishing platform. The publication had grown from the roughly 24,000 free subscribers Newton brought with him when he left The Verge to more than 170,000 at the point of migration. It was one of the most-read independent tech newsletters in the United States, and Substack considered it a flagship.

Newton was leaving over moderation. In November 2023, Jonathan M. Katz reported in The Atlantic that Substack hosted scores of white-supremacist and explicitly Nazi newsletters, including at least sixteen using overt Nazi symbols. On December 21, co-founder Hamish McKenzie responded that Substack would neither remove nor demonetize them. Newton and managing editor Zoë Schiffer identified seven publications they considered to express explicit support for 1930s Nazis and threats of violence. Substack had already removed one. Newton sent the remaining six as a test of the company's stated rules. Substack removed five, declined to commit to a forward-looking policy, and leaked the scope of Newton's findings to a friendlier publication in what Newton described as an attempt to minimize the story.

The core question of the migration was: If one leaves the platform that has been responsible for a meaningful share of your distribution, does the business survive? Two years later, the answer is on the record.

Platformer was not a typical Substack publication. Newton had spent seven years as Silicon Valley editor of The Verge and brought his existing newsletter list with him in October 2020. He arrived with a built audience, not as an unknown writer building one from scratch.

His deal with Substack included logo design, healthcare stipends, and legal support. He kept 90% of subscription revenue and retained ownership of his subscriber list under Substack's standard portability terms. By September 2023, Platformer had 155,355 free subscribers and roughly 5% paying, implying about $775,000 in gross annual subscription revenue. Growth that year was unusually fast, driven by news scoops and Substack's recommendation engine. By the January 2024 migration, the free list had grown to more than 170,000.

Newton was explicit about what made the migration possible. Platformer owned its list. Substack's portability terms meant that subscriber names, addresses, and Stripe payment information were carried over without requiring readers to resubscribe. The next Tuesday edition arrived as usual, only the URL changed.

The risk was that Substack's recommendation network and Notes feature had become a real subscriber acquisition channel, and that Ghost would lose it entirely. Newton acknowledged this directly. New readers on Ghost would have to manually enter credit card details rather than upgrade with one click from the cards Substack already had on file.

By September 2024, eight months later, Newton reported Platformer had 190,196 subscribers, up about 35,000. Growth was slower than in 2023 but more durable. Revenue was up roughly 11% year over year. Part of that reflected keeping the 10% Substack had taken. Part was offset by new expenses such as Ghost Pro fees, Outpost for lifecycle emails, a redesign, and in-house customer service. The publication also launched paid advertising under Schiffer's management and brought in close to six figures of ad revenue in year one. By the fifth anniversary in September 2025, Newton described Platformer as a stable, mature business with thousands of paid subscribers and a three-person newsroom, while acknowledging that growth had slowed further as both Substack's network and Twitter's distribution utility eroded.

Three structural facts explain the outcome. Platformer's authority was its own. Newton had spent seven years at The Verge before launching the newsletter. Readers followed the byline, and the reputation was portable in a way that subscriber lists alone are not.

Substack's terms genuinely allowed the move. The portability clause from 2017 was a deliberate design decision by the founders, who believed that letting writers leave was the only way to convince them to stay. The guarantee was expensive when high-profile writers exercised it, but it was the same guarantee that had pulled them in.

Subscription economics absorb a distribution shock better than ad economics. Platformer's revenue does not depend on monthly traffic. It depends on a few thousand readers continuing to renew. Losing the discovery surface meant slower acquisition of new paid subscribers, not the loss of existing ones.

It would be tempting to read this as evidence that any subscription publication can leave its platform without consequence. The case does not support that. Newton migrated with an established byline, a paying base in the thousands, a co-editor with operational skill, and a moral reason that resonated with his readers. He moved to a nonprofit platform whose policies aligned with his own.

A subscription business whose value derives from the writer rather than from the platform's distribution can absorb the loss of a channel without collapsing. A writer whose audience exists because of platform discovery does not get the same outcome. The list is portable but the relationship behind it is not.

Today, Platformer is smaller in growth terms than it would have been on Substack and larger as a business it actually owns. The lesson is not that every writer should leave their platform. The lesson is that the value of any distribution layer is best measured by what survives without it.

Newton's migration answered a question most operators never get to test directly: whether the audience belongs to the platform or to you.

See you next week.

If you liked this edition of Growth Curve, forward it to a founder or marketer who needs to stop renting their audience — and start owning it.