The Age-Invitation Curve
Target the age band still adding social connections, or plan to buy every user with ads
- Difficulty
- Easy
- Time to result
- ~ongoing to results
- Steps
- 3
- Confidence
- 94%
For social products, a user's propensity to invite others is a predictable function of age. Invitations sent per user drop about 20% for every additional year from 13 to 18, and adoption of new apps largely stops after 22. Building for older users means you lose organic virality and network effects, so you must acquire nearly every user with paid ads and heavy venture capital.
Origin
Nikita Bier's heuristic from building ~15 consumer apps for different audiences, reinforced by academic research (he attributes a study to academics in Spain) showing texting contacts rise until ~21 then collapse.
Core principles
- 01Invitations per user fall ~20% for each year of age from 13 to 18
- 02Adoption of new apps largely stops after about age 22
- 03The number of people you text rises until ~21, then collapses until late life
- 04Target users on the upward curve of adding connections, where urgency to connect is highest
- 05Teens' habits are malleable, they see each other daily, and they invite prolifically
How to run it
- 1
Decide if you need organic network effects
Determine whether your product depends on users inviting other users to create density and value.
- 2
Check your target cohort against the curve
If you need viral invites, target the 13-to-early-20s band still on the upward slope of adding social connections.
Pro tip Highest urgency to communicate (and thus to invite) sits where the social graph is still growing.
Watch out Every year older your audience skews, expect roughly 20% fewer invitations per user across 13 to 18.
- 3
Budget honestly for older audiences
If you build for adults, assume you'll acquire essentially every user through ads and size your fundraising accordingly.
Watch out As a seed-stage startup, financing paid acquisition to reach density for real network effects is basically impossible.
In the wild
Across ~15 apps Bier built for college students, post-college and others, and found the flywheel almost never spun for anyone over 22. He concluded no one needs another app after that age and refocused on teens, whose invite behaviour and daily contact drove viral spread.
→ The teen focus led directly to TBH's explosive school-by-school growth and $30M+ acquisition.
Common mistakes
Building a viral social app for adults
Adults barely invite others, so you forfeit organic growth and must fund expensive paid acquisition to reach density.
Expecting network effects post-22
Habits harden and invitation rates collapse, so getting the flywheel to spin among older users is near impossible for a startup.
Is it for you?
Best for
Social and communication app founders choosing a target demographic
Not ideal for
Paid-acquisition or B2B products that don't rely on user-to-user invitations for growth
From the transcript
“the number of invitations sent per user drops 20% for every additional year of age from 13 to 18. So if you build for adults…”
“it was always very difficult to get the flywheel spinning for anyone after like 22 years old”
“if you really want to actually innovate at the edges of communication products you you you really have to target that cohort that has the…”
From the episode
How to consistently go viral: Nikita Bier’s playbook for winning at consumer apps (co-founder of TBH, Gas, advisor, investor)