Not only does a product have to appeal to the hard side of the network, but as I discuss in “The Killer Product,” the most successful network effects–driven apps are also sometimes dead simple. They eschew a long list of features and instead emphasize the interactions among people using the

First, does the product have a network? Does it connect people with each other, whether for commerce, collaboration, communication, or something else at the core of the experience? And second, does the ability to attract new users, or to become stickier, or to monetize, become even stronger as its network grows larger?

In other words, the ideal product to drive network effects combines both factors: The product idea itself should be as simple as possible—easily understandable by anyone as soon as they encounter it. And at the same time, it should simultaneously bring together a rich, complex, infinite network of users that is impossible to copy by competitors.