Viral Marketing Playbook

You bolted a referral program onto your product and... nothing. People don't share because you asked — they share when the loop is designed into the moment they get value. This playbook is the mechanics of virality, with the math to tell whether a loop will actually compound. What's inside: • Viral loop anatomy — the mechanics behind referral, invite, and content loops • K-factor math — calculate your viral coefficient and model growth scenarios before building • Incentive design — what to offer referrers and referred users (and what quietly kills the loop) • Share triggers — the moments in the user journey where sharing feels natural, not begged • Case studies — how Dropbox, Notion, and Loom built their viral engines 🇨🇳 病毒增长设计 — 病毒循环解剖+K因子计算+激励设计+分享触发时机，含 Dropbox/Notion/Loom 拆解。 🇯🇵 バイラル設計 — バイラルループ解剖、K係数計算、インセンティブ設計、シェアトリガー。Dropbox/Notion/Loom事例。 🇰🇷 바이럴 설계 — 바이럴 루프 해부, K-팩터 계산, 인센티브 설계, 공유 트리거. Dropbox/Notion/Loom 사례. Triggers: "viral marketing" | "viral loop" | "referral program" | "referral marketing" | "K-factor" | "viral coefficient" | "invite system" | "share mechanics" | "network effects" | "growth loop" | "word of mouth" | "病毒营销" | "病毒循环" | "裂变" | "推荐机制" | "バイラル" | "바이럴 마케팅"