Dunbar's number: focusing on your core supporters for network effect growth

In the early days of building a product, focus on building strong connections with small group of people to solicit meaningful feedback and drive network effect growth.

When building something new, it's natural to set your sights on hitting massive growth numbers.

Dunbar's Number suggests that sustainable growth starts smaller than you might think - with a close-knit, trusted network. This social theory, from British anthropologist Robin Dunbar, suggests that we can maintain stable social relationships with around 150 people at most.

But within that 150, there's almost always a much smaller core audience that truly drive connection, influence, and impact.

In the early stages of building a product or service, these core people are your foundation. They're the first to test, trust, and tell others about what you're doing. Nurturing this group can create a network effect that sets you up for growth.

Thank you PostHog for sponsoring

Flex your product muscle
Product for Engineers is a newsletter on building great products, the best practices of top startups, and lessons learned by PostHog.

Subscribe for free

Most people talk about Dunbar's number in terms of 150, but the power lies in close-knit groups of 50. These 50 people are your advocates, your early adopters, your most vocal supporters. For product builders, focusing here first creates a foundation that grows beyond one-time use or sporadic engagement.

1. Quality over quantity: Building a strong network starts with a core group of advocates. These 50 people are your most engaged users, the ones who will spread the word and bring others in.
2. Network effect: When you focus on building a strong core group, you create a network effect that drives growth. These advocates bring in others who trust their recommendations, creating a ripple effect.
3. Sustainable growth: By nurturing your core 50, you create a foundation for sustainable growth. These advocates will stick with you through changes and challenges, helping you build a strong, resilient network.

My advice is to build with your core 50 in mind. Focus on creating a product that meets their needs, listens to their feedback, and adapts to their preferences. By doing so, you'll create a network that grows naturally, sustainably, and with trust at its core.

This is why many startups begin with a friends and family launch. It's a great way to get blunt feedback from people who care about you and your success, and who can be trusted to give you honest feedback.

Gore, the company that makes of GORE-TEX, applies Dunbar's number by limiting the size of its factories. When a team hits 150 people, they spin off a new group. Each group operates independently with its own R&D, production, and sales teams. This approach keeps teams close-knit, engaged, and highly collaborative—key to their success.

Nurture Your Core 50: Focus on building meaningful relationships with your first 50 users. They are the heart of your network, and their enthusiasm will drive momentum. Treat their feedback like gold, and respond to their needs directly. Create a Product of Substance: Deliver on your promises to these early adopters, listen actively, and adapt. A strong, attentive foundation encourages your core group to bring others in naturally.

For your product: Build with compassion and responsiveness. Turn your initial 50 users into advocates so they bring their own circle along.

It's Election Day: Influence your Dunbar network. Encourage the people you know best to vote today - your voice has power, especially in small circles.