Word of Mouth Beat Everything

The Story

“I’ve tried everything — paid ads, SEO, biz dev — and none of it really did a damn thing. Word of mouth was the biggest lever.” (Source 1).

Tactics that didn’t work for Lenny: Twitter ads, referral programs, cross-promotion with other newsletters (Source 2).

Tactics that did work: guest posts on Andrew Chen’s blog and First Round Review, Twitter engagement and thread summaries, and the initial audience leverage from existing followers (Source 2).

He posted weekly without fail for 5+ years (Source 1). He expanded beyond product management to include startup building, career development, and product growth (Source 1). 8 of his top 10 posts in the “Growth” category are guest pieces, and he goes through 5-6 draft revisions with each guest writer (Source 1).

By 2025, over 5,000 Substack newsletters recommended his publication (Source 1). Substack’s recommendation feature, launched in April 2022, became a significant growth driver. Substack drives 78% of his free subscribers and 12% of new paid subscribers via discovery (Source 3).

He operates primarily solo as the sole full-time employee, hiring contractors only for podcast-related tasks (Source 1). He has observed that creators leaving Substack see growth slowdowns, and remains on the platform despite the 10% fee because “the platform pays for itself through subscriber discovery features” (Source 3).

Lesson for Creators

Lenny tested nearly every growth tactic in the newsletter playbook, and most failed. The only thing that consistently worked was making content so good that people shared it unprompted. This is both the simplest and hardest growth strategy: it can’t be hacked, shortcut, or automated. The 5,000+ newsletter recommendations are a compound effect of years of consistent quality. For creators debating between growth tactics and content quality, Lenny’s data is unambiguous: quality is the tactic.