The complexity and dynamism of the environment due to rapid technological changes on the one hand, and increased Internet influence and on the other hand have affected various aspects of business and human life and the geographical and economic boundaries have been disappeared. They have also caused commercial and economic activities, ranging from financial transfers, marketing and sales, as well as the provision of services and follow-up for consumers to be taken into consideration. Thus, modern marketing practices have been developed in light of Internet and social networks, which one of them is the viral marketing. It is is based on word of mouth advertising principle and dissemination on the Internet and the use of social networks and cyberspace. Therefore, to succeed in viral marketing, it is important to consider some of the factors. The objective of this article is to examine the related studies in this field and to provide a definition of viral marketing and to examine the factors affecting its success. Finally, some points to be successful in this field along with applied examples would be provided.
