Metric · Hooked
Referral share of activated sign-ups
Share of new activated users who came through another user (an invite, a referral link, a shared result). The primary Spread metric; referred users should retain at least as well as organic ones.
Plain label: new activated users who came through other usersAlso known as: referral share, word-of-mouth share
Guardrails: referred-user day-30 retention and refunds versus organic users, and invite spam reports. On Recall & Trust routes this is the headline metric next to repeat rate, with reviews and referrals asked right after the moment of value.
Limits
What we don’t claim
- The Hook Model is a practical design tool, not a validated or complete theory of behavior.Hooked, Introduction
Sources
Hooked · Nir Eyal
Ch.2
Source IDs: HK-TRG08
Book content is paraphrased, never quoted at length. Last verified October 24, 2026.
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