The buzzwords viral marketing and viral advertising refer to marketing techniques that use social networks to produce increases in brand awareness or to achieve other marketing objectives through self-replicating viral processes, analogous to the spread of pathological and computer viruses.

Viral promotions may take the form of video clips, advergames, ebooks, brandable software, images, or even text messages.

The assumption is that if such an advertisement reaches a susceptible user, that user will become infected (i.e., accept the idea) and will then go on to share the idea with others infecting them.

This Guy is a Viral Example