We hear a lot about viral marketing these days, and especially viral videos. This method of exposure is pretty easy to understand, actually; it’s just word-of-mouth, but on the internet. “Viral” refers to the contagious nature of successful viral marketing. One person enjoys it and spreads it to two other people, those two spread it to two other people, and so on and so on. This is why someone can post a two minute video on Youtube, show it to a few friends, and within a week have hundreds of thousands of views.