Sponsored content has gained popularity as a digital media marketing tactic. Brands collaborate to create sponsored content with the so-called new-media influencers who are able to gather significant audiences and are claimed to offer a new form of authenticity. The paradox between the audiences' expectations of authenticity and the commercial intentions of marketers is potentially complex and confusing. Hence, more insight is needed of how consumers react to sponsored content.

The objective of this thesis is to explore how priming influences the authenticity and source credibility perceptions of vlog-viewers along with their emotions. Particular attention is paid on authenticity as a less studied concept. To study the effects of priming, this study uses four different manipulation conditions to influence a vlog-viewing experience and therefore the responses of the viewers to the content.

A theory-guided content analysis of 213 open responses was conducted to compare the differences of authenticity and credibility perceptions as well as emotions between the manipulation groups. As another outcome of the analysis, a concept of source authenticity was formed. Also, a separate emotions analysis was conducted.

The results suggest that priming shapes the authenticity and source credibility perceptions of the vlog-viewers, which is verified by chi square tests. The emotion analysis suggest that mixed manipulation conditions lead to more mixed emotions and that negative emotions are mainly directed at the endorser and least at the products. An authentic source was defined as genuine, unbiased, relatable, and passionate. In addition, charisma and funniness were suggested to be included in the definition together with trustworthiness.

The conceptualization of source authenticity formed in this study gives insight on what viewers pay attention to when evaluating the authenticity of a source. The results of this study offer practical viewpoints to communication and marketing professionals especially for managing collaborations with new-media influencers. However, more research is needed to further develop the concept of source authenticity and to study its effects.