In our society, people are now bombarded daily with countless advertising messages. Due to this overload, consumers build a kind of defense shield against advertising. As a result, many advertising messages no longer reach consumers today, and the often-used advertising principle 'More is more!' is increasingly losing its validity. For many advertisers, viral advertising is seen as the solution to this problem. They believe that this form of advertising can counteract the reactance towards traditional advertising. The idea that customers will spread advertising messages among themselves epidemically is often hailed as an advertising or marketing miracle weapon. This book highlights the peculiarities of viral advertising and discusses its opportunities and dangers. In a further step, viral advertising is differentiated from traditional advertising and other online advertising forms.