Each of these beta customers formed an atomic network—a stable, self-sustaining group of users who can drive a network effect. Once an atomic network was formed in one of their beta testers, Slack would continually add users, become more useful, ramp up engagement, and ultimately become the de facto method of communication within their workplaces.

My advice: Your product’s first atomic network is probably smaller and more specific than you think. Not a massive segment of users, or a particular customer segment, or a city, but instead something tiny, maybe on the order of hundreds of people, at a specific moment in time.