The Adjacent User Theory
by Bangaly Kaba • Director of Product Management at YouTube
Former VP of Product at Instacart, Head of Growth at Instagram, Early Growth PM at Facebook. Started career in education as a teacher and dean.
🎙️ Episode Context
Bangaly Kaba joins Lenny to share his frameworks for career navigation and product leadership, drawing from his experience at YouTube, Instagram, Instacart, and Facebook. He breaks down his 'Impact Career Equation' for evaluating roles, the 'Understand Work' operating model for de-risking product bets, and the 'Adjacent User Theory' for driving sustained growth. He also discusses the '5-Box Change Diagnostic' for managing team culture and the importance of leadership as a coaching practice.
Problem It Solves
Sustains growth when early adopter segments are saturated; prevents designing only for power users.
Framework Overview
A growth strategy focused on identifying and solving for the user segment immediately outside the current core user base—people who are aware of the product but struggle to adopt it due to specific barriers.
🧅 Layer Model
When to Use
When cohort retention curves start to decline or when entering new markets/demographics.
Common Mistakes
Assuming the new user is just like the old user; failing to test the 'cold start' experience; relying on power user feedback.
Real World Example
Instagram's growth in India required understanding adjacent users who relied on 'Amit Kumar' searches (names) rather than profile metadata, leading to a shift in how connections were surfaced.
You've got to be on top of who you believe the next user is... and literally see what they're doing in real time in order to make sure that you're enabling the right jobs for them.
— Bangaly Kaba