Zhang Yiming

Zhang Yiming built a video app and watched people scroll for four hours continuously. Content was grainy. Creators unknown. Yet users scrolled past friends' videos seeking recommendations. The algorithm mattered more than content. Facebook served people you followed. TikTok was different. TikTok's algorithm served content about topics you never searched. It discovered what would keep you watching longest. Addictiveness became the optimization. TikTok grew from zero to a billion users in five years. Growth was driven by the algorithm's ability to surface content to likely viewers. A creator with zero followers could reach a million viewers if the algorithm believed content would drive engagement.