Some Interactions Are More Equal Than Others: The Effect of Influencer Endorsements in Social Media Brand Posts on Engagement and Online Store Performance

This study investigates the value of influencer endorsement within brand-owned social media posts in terms of engagement and online store performance. Specifically, it focuses on how endorser-caused engagement translates to online store performance. The authors examine metrics that capture short-term performance (online shop visits and immediate sales) by tracking immediate responses to social media posts. They conduct an empirical analysis based on real Facebook posts published over 1.5 years by a leading European online fashion retailer that targets young adults. To confirm results and shed light on the underlying mechanisms, the authors further conduct a randomized online experiment (N = 305) that mimics the field study. They find that influencer endorsements are associated with increased engagement and that engagement is associated with higher online store performance. The results show that endorsement negatively moderates the effect of engagement because it distracts from the products (i.e., the “vampire effect”). The authors conclude that consumers’ underlying intentions of engaging with social media posts vary, which implies that engagement caused by an endorser has less economic value than engagement motivated by other (e.g., product-related) reasons. From a practical perspective, social media brand post endorsement should be considered a tool for brand marketing rather than for performance marketing, and social media metrics should be interpreted with care, because not all engagement may help online store performance.