While social media has become an integral part of modern-day life, it is a largely overlooked topic in supply chain business-to-business setting. This study utilizes dyadic survey data collected from both supplier account managers and their customers to explore social media's impacts in the digitalized supply chain context. Drawing upon the knowledge-based view of the firm, the study proposes and tests a conceptual model. Results indicate that supplier account manager's social media use can increase his or her product and competitor knowledge, which can positively influence customer outcome. Further, the moderation test suggests that when perceived customer demandingness is high, the relationship between social media use and knowledge will be stronger. This study draws much-needed attention to social media as an emerging digital supply chain management too.