Hooked: How to Build Habit-Forming Products

by Nir Eyal

Facebook’s success was, in part, a result of what I call the more is more principle—more frequent usage drives more viral growth. As David Skok, tech entrepreneur turned venture capitalist, points out, “The most important factor to increasing growth is … Viral Cycle Time.”7 Viral Cycle Time is the amount of time it takes a user to invite another user, and it can have a massive impact. “For example, after 20 days with a cycle time of two days, you will have 20,470 users,” Skok writes. “But if you halved that cycle time to one day, you would have over 20 million users! It is logical that it would be better to have more cycles occur, but it is less obvious just how much better.”