The topic of this final thesis is "Forms of viral marketing on the Internet". The paper defines the concept of digital marketing as well as its forms. The basis of the theoretical part of this final paper is the conceptual definition of viral marketing as well as its detailed elaboration. The paper describes its development throughout history and its basic forms that are used today for the purpose of promoting and advertising certain products, services and brands. Viral marketing stands out due to its many advantages, which are also the reason why many business entities of some of the world's largest organizations decide on this form of marketing when creating their campaigns. On the other hand, viral marketing has several disadvantages, and one of the fundamental disadvantages is its unpredictability. Business organizations that choose viral marketing assume a certain risk and responsibility if the campaign does not result in the expected success. Also, the communication channels of viral marketing as well as its impact on society are listed in the paper. Viral marketing is closely related to society and has an impact on the individual precisely because it depends on the users themselves; consumers are encouraged to interact, give their opinion, share their experiences and information related to products, services or brands. In the second part of this final paper, some examples of viral marketing on the Internet are described. Examples include Dove and Coca-Cola, which are considered the main organizations for creating viral marketing campaigns on a global scale. Along with the previous two organizations, Apple certainly stands out when creating viral campaigns, so that was the reason for discussing it in this final paper. As previously mentioned, viral marketing is unpredictable and a large number of times when something is perceived as having a good potential for success it turns out to be the exact opposite. One such example is the Osijek brewery campaign, which is discussed as the last example in this final paper.