The buzzwords viral marketing and viral advertising refer to marketing techniques that use pre-existing social networks to produce increases in brand awareness or to achieve other marketing objectives (such as product sales) through self-replicating viral processes, analogous to the spread of pathological and computer viruses.
It can be word-of-mouth delivered or enhanced by the network effects of the Internet. Viral promotions may take the form of video clips, ebooks, brandable software, images, or even text messages.
The goal of marketers interested in creating successful viral marketing programs is to identify individuals with high Social Networking Potential (SNP) and create Viral Messages that appeal to this segment of the population and have a high probability of being taken by another competitor.
In a more basic application, viral marketing attempts to use social networks to create a “buzz” about a product of service. Many times a unique event, such as a video, is used to draw attention and the product or service is a subliminal part of the message.
Simply allowing your website or content to be easily shared among others is the simplest way to start. The use of social network feeder streams  like ShareThis, is a great way to allow the visitor to choose which venue they prefer.
It alleviates the current practice of showing multiple SN icons, usually at the bottom of the page, Â which most visitors never use.