Adjacent User Theory

Grow by understanding and enabling users just outside your current base

Bangaly Kaba
Unorthodox frameworks for growing your product, career, and impact

Adjacent User Theory

"Really talking to who is just outside of your current user base, who's coming to your product and looking around and not buying, and understanding what are their needs." - Bangaly Kaba

What It Is

Adjacent User Theory is a growth framework developed at Instagram for understanding who your next users will be and what they need. Your current users are already well-served by your product—growth comes from the adjacent users: people just outside your current user base who could use your product but for whom something isn't quite working.

This framework is essential for hypergrowth companies (30-50%+ annual growth) and useful for any company trying to expand their market. The key insight is that adjacent users have different needs, contexts, and behaviors than existing users—and if you build only for power users, you'll miss the next wave of growth.

How It Works

Understanding Adjacent Users

Adjacent users are characterized by:

  • They could use your product but currently don't (or churn early)
  • Something about the product doesn't work for them
  • They may be less tech-savvy or have different contexts
  • They're on the cusp of the early adopter / late majority boundary
  • They experience your product in a "new account" state, not a power user state

Signals That Adjacent Users Are Arriving

  1. Cohort Curves Decline: Users who sign up today perform worse 3-6 months later than users who signed up 6 months ago, even though the product hasn't changed.

  2. New Markets Open: Expansion into new geographies brings users with different phones, internet access, and cultural contexts.

  3. Retention Dips: After initial adoption, you see retention flatten and then dip—a sign that adjacent users activated but couldn't build a habit.

The Power User Trap

The product you use as a power user is not the product your adjacent users experience:

  • Power users have rich history, established connections, and trained algorithms
  • Adjacent users have empty feeds, no friends, and generic recommendations
  • Creating a new account reveals the gap between these experiences

At Instagram, this manifested as "all follows were created equal"—the system optimized for any follow, which meant celebrities got recommended to everyone. But regular users would follow celebrities, post content months later, and get no engagement because no friends followed them back. They'd leave feeling ignored.

How to Apply It

  1. Create New Accounts: Regularly use your product in an adjacent user state. Create fresh accounts. Experience onboarding as a newcomer.

  2. Dogfood as Adjacent Users: Don't just test as yourself—test as the persona of someone less familiar with your product.

  3. Visit Users In Context: Go to where adjacent users live. Bangaly's team went to India every three months to watch people use Facebook in their actual environment.

  4. Look for Cultural Assumptions: What works in your home market may not translate. Facebook's profile fields (school, job title) meant nothing to users whose friends "sell jeans at a market."

  5. Research Cohort Differences: Compare behaviors between cohorts from different time periods. What's different about users who signed up this month versus six months ago?

  6. Solve for the Adjacent Job: Adjacent users often have different jobs to be done. Instacart's original user was an office admin ordering for happy hours; the adjacent user was a parent with three kids who needed convenience.

  7. Accept Product Changes: Serving adjacent users may require rethinking core product assumptions. Instagram had to deprioritize celebrity recommendations for new users to enable friend connections.

When to Use It

  • Required: If you're growing 30-50%+ annually (hypergrowth)
  • Valuable: When trying to expand into new segments or markets
  • Diagnostic: When retention curves are flattening or declining
  • Strategic: When deciding which features to build for growth vs. engagement

Source

  • Guest: Bangaly Kaba
  • Episode: "Unorthodox frameworks for growing your product, career, and impact"
  • Key Discussion: (01:03:29) - Framework explanation and Instagram examples
  • YouTube: Watch on YouTube

Real Examples

Instagram: The Connections Pivot

Adjacent users were signing up, following celebrities (because that's what was recommended), and retaining for 7-8 months. Then retention would dip again—unusually.

Investigation revealed: when these users finally made their first post, no friends were following them. They were posting into an echo chamber and felt bad about the lack of engagement.

The solution: prioritize recommending friends over celebrities for new users. "Get people connected with their friends early on so when they make their first post, their friends see it and they feel validated."

Result: Retention doubled over 18 months.

Facebook India: The Amit Kumar Problem

Facebook's people recommendations seemed broken in India—fewer friends in common, strange friending/unfriending patterns.

On-the-ground research revealed: The most common name was Amit Kumar, with 250,000+ real users. When someone in Bangalore searched for their friend "Amit Kumar," they might get 5,000 possible matches. Profile fields (school, job) were meaningless because friends "sell jeans at a market."

Users had developed workarounds: scrolling through photos to identify friends by their car or pet, not by profile data.

The cultural context was completely different from Western assumptions.

Related Frameworks

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