The solution to the Cold Start Problem starts by understanding how to add a small group of the right people, at the same time, using the product in the right way. Getting this initial network off the ground is the key, and the key is the “atomic network”—the smallest, stable network from which all other networks can be built.

The reality is that new products are often greeted by a nice initial spike of users, but this falls to a trickle as the novelty wears off. Maybe there’s another push, which again goes nowhere. People won’t use their product unless their friends are on it. Features are feverishly added, marketing efforts are redoubled, but the network never gets off

How do you build network effects in your product? How do you know when network effects are kicking in, and if they are strong enough to create defensibility? How do you pick the right metrics to optimize to achieve viral growth, reengagement, defensibility, and other desired effects? What product features do you build to amplify network effects?