At the time when social media is ruling the world and free fashion and makeup products are given as an exchange for a promotion video or a photo on some social media platform, it is essential to point out the business side of all those pretty photographs and videos from exciting locations where all expenses are paid. This paper points to exactly that. In addition to defining and explaining key terms relevant for this paper such as social media, Instagram, YouTube, influencers, influencer marketing, this paper shows how marketing was adapted to the online world, adding to a complete change in relations between the public and brands. The main focus of this paper are influencers as popular platform users with a large following and large profits. Who, by working with brands and companies, became a true link between the public and brands. Therefore, the research this paper addressed were ways influencers are running their social media business: are they or are they not transparent with their audience about their paid collaborations and sponsorships. The goal was to answer the questions about whether influencers (both Croatian and foreign) inform their followers or not, how successful are they, how many sponsored posts do they have and how brands use their profiles on selected social media platforms such as Instagram and YouTube. The research was conducted by the method of content analysis, analyzing all content published within one year. Key words: social media, influencers, Instagram, YouTube, online marketing