The storyHow they got there
Josh Comeau spent years writing free interactive CSS tutorials on joshwcomeau.com — genuinely excellent content that spread because developers forwarded it to colleagues. "An Interactive Guide to Flexbox" became a canonical resource. None of it was monetized. None of it was trying to convert.
The first ten buyers were newsletter pre-sales to engaged subscribers. The first hundred — and the first thousand — came from a single launch sequence: an email to a 30,000-subscriber newsletter built over years of free content, combined with Twitter announcements to 31K followers. The infrastructure was the audience.
The channel mix at launch: personal blog interactive posts (~60% of all signups sourced here), newsletter list as the primary paid conversion driver (~50% of paid conversions despite being "downstream" of the blog), Twitter (~20% of signups), and word-of-mouth and developer community shares (~15%). Paid ads were never considered. The interactive blog posts as long-term lead magnets were the engine.
Unit economics: course price $400–600, CAC effectively $0 (audience-driven), refund rate around 3–5% (industry-leading low), effective margin above 90%. One week's launch generated $577K in revenue and ~4,773 orders. The lesson is about time horizon: 12+ months of genuinely useful free content beats any paid acquisition strategy for course launches.
Channel MixWhere the growth actually came from
Most case studies hand-wave channels. Here's the rough allocation — not in dollars spent, but in users acquired — across the routes that actually mattered.