Mastodon vs Substack

Mastodon

Decentralized, open-source social network

Mastodon is open-source, decentralised microblogging. Instead of one company running one site, anyone can run a server - an instance - and those servers talk to each other over the ActivityPub protocol, so an account on one can follow, reply to, and boost accounts on any other. Collectively that network is the fediverse. The design decision that follows from this is the one that matters. There is no global algorithmic feed. Timelines are chronological, there is no advertising, and moderation policy is set by whoever runs your instance rather than by a single global trust-and-safety team. That makes moderation local and legible - you can read your server's rules and know who enforces them - and it means the experience varies by server, which is genuinely a trade-off rather than a pure win. Choosing an instance is a real onboarding cost that centralised platforms do not impose, and it remains the single biggest reason people bounce. For a founder or an organisation, the practical appeal is ownership. You can run your own instance on your own domain, verify your identity through a link on your own website, and keep an audience that no acquisition or policy change can take away. Account migration is built in: you can move to a different server and bring your followers with you, which structurally limits how much leverage any one operator holds over its users. The numbers are worth stating plainly rather than optimistically. Mastodon peaked at roughly 2.6 million monthly active users in November 2022, immediately after Twitter's acquisition, and has settled to somewhere between 750,000 and one million monthly actives in 2026, spread across thousands of instances. The wider fediverse has passed 11 million registered accounts with one to two million active. It is a real, durable network, and it is not a mass-market replacement for a large social platform. Governance changed in 2025 and 2026. Founder Eugen Rochko stepped down as CEO after ten years and the project completed a transition to a non-profit structure with more than 3 million euros in funding and a board that includes Twitter co-founder Biz Stone, explicitly to make the platform, in its own phrasing, hard for any single wealthy owner to capture. Funding comes from donations and grants rather than advertising. How it compares: Bluesky is the closest peer and is also protocol-based, but is easier to join and more centralised in practice; Threads is federating slowly and is owned by Meta; X is the incumbent it was built to be an alternative to. Mastodon's distinguishing claims are no ads, no algorithm, and no owner. It suits communities and individuals who want portability and local moderation. It is a poor fit for anyone whose goal is maximum reach.

Substack

Publishing platform where writers own their audience

Substack is a publishing platform for newsletters, and its defining decision is that it charges nothing until you charge your readers. You write in a plain editor, it emails the post to your list and publishes it as a web page, and if you turn on paid subscriptions it takes a cut of the revenue. There is no monthly fee at any list size, which is why it became the default for writers starting from zero. The platform now covers more than email. Posts can carry paywalls at the post or section level; there is podcast hosting with private RSS feeds for paying subscribers, video, threads and chat for community, and Notes, a short-form feed that has become a meaningful growth channel. Recommendations let publications refer readers to each other, and this network effect is the real product: a Substack with no audience is discoverable in a way that a self-hosted newsletter is not. The economics: publishing free is $0. On paid subscriptions Substack takes 10% of revenue, and Stripe takes its own processing fee on top — roughly 2.9% plus $0.30 per transaction, with an additional recurring-billing fee — so budget 13-16% of gross rather than 10%. On a $10 monthly subscriber you keep somewhere around $8.40. That is excellent at small scale, where a fixed platform fee would exceed it, and expensive at large scale, where 10% of a six-figure revenue line buys a lot of alternative tooling. What "owning your audience" actually means here is worth being precise about. You can export your subscriber list, including paid subscribers, and move to another platform, and you can point a custom domain at your publication. What does not travel is the network — the recommendations, the Notes feed and the Substack app that were sending you new readers. That is the lock-in, and it is a real one. Beehiiv is the closest competitor and is built for growth mechanics and ad monetisation, with tiered flat pricing that beats 10% once revenue is meaningful. Ghost is the open-source option: a flat platform fee or self-hosting, no revenue share, full ownership, and no discovery network to lean on. Kit (formerly ConvertKit) is the choice when the newsletter is a funnel for other products rather than the product. Buttondown is the minimal, developer-friendly option. Patreon is better when the offer is membership access rather than writing. Choose Substack to start writing today and let the network find your first thousand readers.