Social Media Influencer Marketing: Evolution, Sales Impact, and Trust-Based Challenges

Abstract

This paper examines the evolution of social-media influencer marketing and addresses two questions: the current state of online influencer marketing (OIM) and its impact on sales performance. Within eight years global expenditure rose from USD 1.7 billion to USD 16.4 billion, confirming the channel’s shift from peripheral experiment to mainstream platform. Influencers enhance sales through three levers—demand activation, fourdimensional efficiency (cost, speed, targeting, conversion) and person-to-person trust—yet simultaneously expose firms to four challenges: integrity gaps between online and offline messages, privacy leakage across platforms, absence of face-to-face emotional reassurance, and overconcentration of sales on single SKUs. The live-stream controversy involving Li Jiaqi and Huaxizi eyebrow pencils demonstrates that sales can plummet as rapidly as they rise, proving that advantages and risks amplify at the same speed. The existing evidence base is skewed toward young and middle-aged consumers, while behavioural patterns of older and cross-cultural populations remain under-explored. Future studies should broaden age and cultural coverage, integrate survey instruments with platform-side log data, and employ longitudinal designs to test whether the documented benefits and drawbacks apply universally, thereby closing the current knowledge gap and providing a robust foundation for scholars and practitioners in the expanding field of influencer-driven marketing.