Viral marketing refer to marketing techniques that use pre-existing social networks to produce increases in brand awareness, through self-replicating viral processes, analogous to the spread of pathological and computer viruses. It can often be word-of-mouth delivered and enhanced online; it can harness the network effect of the Internet and can be very useful in reaching a large number of people rapidly.
Viral marketing sometimes refers to Internet-based stealth marketing campaigns, including the use of blogs, seemingly amateur web sites, and other forms of astro-turfing, designed to create word of mouth for a new product or service. Often the goal of viral marketing campaigns is to generate media coverage via "offbeat" stories worth many times more than the campaigning company's advertising budget.
The term "viral advertising" refers to the idea that people will pass on and share interesting and entertaining content; this is often sponsored by a brand, which is looking to build awareness of a product or service. These viral commercials often take the form of funny video clips, or interactive Flash games, an advertising game, images, and even text.
