This chapter is probably why you picked up this book in the first place. Many people wonder how things (videos, sites, news, and so on) “go viral” online—diffuse rapidly and become a part of the culture (and in the process, make their authors rich). We should forewarn you that we have no ready-made recipe. Nobody really has a recipe, and there is a fair bit of luck involved—but in this chapter we’ll try to get you closer to understanding what drives diffusion and how your decisions can drive adoption of a product.
Let us suppose that you made a really cute video of your cat, posted it on YouTube and Tweeted about it. Are you on your way to riches? Well, it depends.
It largely depends on who sees it and what they do with it afterwards. At first, the only people that see it are in your immediate ego network—i.e., your friends. As such, growth in the number of views is very slow; it is linear over time, meaning that views happen at a constant rate. In this case, we can describe the number of views as a Poisson process, where every act of viewing your cat video is independent of every other act. At the end, the total number of views you would get would be mathematically related to the number of followers you have—your degree centrality.
But if something else happens and your friends retweet the video to their friends (and so on, exposing more and more people to it), your cat is suddenly in the most popular video on YouTube, ...