How does viral marketing help in driving traffic to your web site for free? Well, as you probably know, viral marketing is when one person passes on marketing information to another person either by word of mouth, or some sort of recommendation. Viral marketing, in a nutshell, is when you get others to market for you at no cost. Now the good thing about viral marketing is that it allows you to be able to generate huge sums of traffic very quickly. It is very possible to generate hundreds of thousands of visitors quickly because of the viral nature of this marketing approach.