The concept of viral marketing has been researched for many years but has earned a new meaning with the intense use of social networks, which have become essential part of our daily lives. The use of social media applications provides not only countless possibilities of advertising and commerce, but also instant communication between marketers and consumers. The new types of 'opinion leaders', who spread electronic word of mouth through numerous platforms such as YouTube or Instagram, are labelled 'social media influencers'. In this paper, we explore the relationship between social media influencers, viral marketing, and bridges between related concepts to better understand and improve online marketing strategies. Although many researchers address various concepts on interrelated topics, the questions of origin of virality remain unclear.