Design a viral loop

Virality is engineered, not luck. A viral loop is a self-reinforcing cycle where each user brings in more users. The measurable north star is the viral coefficient K = i × c, where i = invites sent per user and c = conversion rate of those invites. K > 1 = exponential growth; K = 1 = stuck; K < 1 = growth dies without paid. (Yotpo)

Reference benchmarks: Slack peaked at K ≈ 8.5; early Facebook ≈ 7. TikTok acquired 6.4 new users for every 1 acquired via paid marketing by watermarking shared videos and prioritizing cross-platform sharing. (molfar.io)

The loop anatomy

User gets value → prompted to invite at peak moment → invite sends a shareable artifact
→ new user sees it → lands on a low-friction onboarding → converts → repeats the cycle

Every stage has a lever. Raise i (more invites per user) or raise c (better conversion of invites) to push K toward and past 1.

Levers to raise i (invites per user)