Through text messages, funny video clips, images, advergames and interactive games that act as promotions, people are often encouraged to voluntarily pass on advertising or marketing messages. This is quite similar to the spread of computer or pathological viruses. Though the Internet's network helps to enhance the effect, these can often be delivered through word-of-mouth. Such techniques that make use of social networks that are already in existence, to help raise awareness about certain products and services, are referred to as viral marketing and viral advertising.

These are based on human behavior that is absolutely natural, as people tend to tell others about services and products that they find useful, as well as those that they do not find satisfactory.

As marketers want messages for viral marketing to be passed along as often as possible, they have to not only create messages, the probability of which to be passed along is substantial, but also to identify people whose potential for social networking is quite high. Then, they try to design messages that are likely to appeal to those kinds of people.

Campaigns for stealth marketing may also be referred to, at times, as viral marketing, though in a bad way. These tend to make use of offline as well as online astroturfing, in order to falsely create an impression of enthusiasm that is spontaneous.

A study has found that a user is likely to share the details of his or her shopping experience, online, with at least twelve other people, on an average. Positive as well as negative experiences are likely to be discussed, in this manner. Therefore, viral marketing and viral advertising can be a powerful marketing tool that aids in the attainment of a business? goals. This is especially so as consumers become even more selective about the advertisements that they watch.

As people increasingly tend to believe viral advertising messages more often than the advertisements that they see otherwise, marketing plans have begun to have viral components as integral parts. This is all the more so as this happens to be a low-cost alternative.

Viral marketing and advertising are increasingly leveraging the Internet, as it is a medium that thrives on account of being collaborative. It is important, of course, that the message is found to be intriguing by people, so that sufficient interest is generated.

Industry pundits, advocates of privacy and consumers have been reacting negatively as well as positively to viral campaigns and these have received their share of attention in the news media. This is especially so in the case of promotional email campaigns those encourage users to refer their friends.

The marketers can reach a group of people that is far larger than the original group targeted by them, through such campaigns, and maximize the returns on their investment, if they carefully manage the concerns over the sending of emails that are unsolicited.

Some ideas aimed at the effective management of such campaigns are as follows:

An incentive should be offered.

However, even as the incentive should be of value to the target audience and tangible as well, it should also have well defined and specific limits. For instance, an individual may be offered a certain percentage as discount on a purchase, if he or she refers a certain number of friends. Such an approach can prevent the forwarding of the message from reaching unmanageable proportions and, therefore, being labeled as spam, causing privacy, financial and customer service-related issues to crop up for the marketers.

Opt-ins should be clearly distinguished from referrals.

When a friend is referred by a customer, it is clearly a referral. This should not be thought of as an opt-in. Therefore, the person's email address and name should not be stored in the company's database, after he or she has referred a friend. Also, an unsubscribe option should be provided within the text of each referral message.

The referral email should be personalized.

People are more likely to respond, when they see that a message has been sent by an identifiable source. Therefore, the subject line of the email should, wherever possible, include the name of the person who has referred the promotional message to the addressee, besides brief details of the offer being sent through the email.

The results should be tracked.

Conversion rates, click-through, pass-along rates and other such important metrics should be tracked and analyzed, to measure as well as improve performance of the campaign.