In Internet and online advertising viral marketing is a type of marketing technique that relies on and encourages people to pass along a marketing message by word-of-mouth (or word-of-e-mail) marketing. Viral marketing online uses blog and social networks to produce positive word-of-mouth brand awareness.
The advantages of viral marketing are low costs, great reach, high credibility, high efficiency and the possibility of continuous campaign adjustments.
The downfalls of viral marketing include the extent of the reach of failed campaigns, the lack of control, risks that the viral message is perceived as spam and the limited possibility for segmentation. One of the things you definitely want to avoid is people being so repulsed at the message (either the words are sick or the images are disgusting) that they do not pass it on, and in fact consider the topic negatively in the wrong way.
