In the context of marketing, the term viral refers to a style that maximizes the use of available social connections in order to increase the effectiveness of promotions. This technique is tagged as such because much like a computer virus, it should spread easily and quickly on its own.

Viral marketing relies heavily on word-of-mouth, or at least on highlighting the idea that something is spontaneously becoming popular due to an increase in public demand.

One of the considerations of a viral marketing campaign is knowing which networks or entities have a high social networking potential, which will facilitate the self-replication of a promotional activity. If enthusiasm is generated in the initial users, then they will share the idea with other users within their own networks.

Since viral marketing involves the spread of a message within and across networks, it usually takes place on the Internet, which allows information to be transferred from one user to another at lightning speed. The use of social networking services also allows users to share their opinions on things they are interested in. Thus, social networking sites such as Facebook, which allow users to post videos or other material which has caught their attention, can be valuable tools in the launch of viral campaigns.

Since this technique is heavily reliant on user interest, it is a relatively inexpensive way of getting a message across to an attentive audience. At the same time, it also poses a greater challenge to the creators of a campaign, as the message must be compelling enough, or the form it comes in should be interesting enough for users to want to share it with others. Some messages may make use of humor, while others may propose incentives for spreading the word.

Neil Stephenson’s early 1990s novel Snow Crash offers an interesting theoretical perspective on viral information.