SNS-based exposure influence on consumers’ purchasing behavior: The evidence from WhatsApp

Abstract

With over 2 billion users globally, WhatsApp has emerged as a distinctive social commerce platform; however, its role in shaping consumer purchase intention remains underexplored. Drawing on the Stimulus–Organism–Response (S-O-R) framework, this study investigates how exposure to promotions on WhatsApp influences purchase intention, mediated by perceived credibility and moderated by differentiated social ties (strong, weak, hierarchical, and tastemaker). Survey data from 309 WhatsApp users in Sub-Saharan Africa were analyzed using covariance-based structural equation modeling. Results confirm that exposure significantly enhances perceived credibility, which in turn positively influences purchase intention. Additionally, social ties strengthen the exposure–credibility link, emphasizing the role of peer trust and tie strength in shaping consumer behavior. The study advances social commerce literature by extending the S-O-R model to encrypted, peer-driven platforms and by operationalizing tie typologies within credibility formation. Practical implications include strategies for businesses to leverage micro-influencers, community-based promotions, and trust-enhancing content tailored to different social ties. © 2025 The Author(s)