隨著以電腦為媒介環境與網路的普及，社群網站紛紛出現。社群網站不僅改變人們溝通 與知識分享的方式，也創造出社群經濟 (Socialnomics) 與社群商務 (Social Commerce)，因 而吸引研究者及行銷人員的興趣。過去社群網站研究聚焦於使用者行為，且大多採用探 索性的研究途徑。本文提出一個整體架構，視社會資本的三個面向（結構、認知與關係） 為社群網站使用者知識分享行為的影響因素，並以使用者心理安全與知識分享自我效能 作為中介變數。本文使用439 位Facebook 使用者的問卷調查結果，以結構方程式模型驗 證理論架構。結果顯示：認知社會資本對使用者在Facebook 上的知識分享行為有著最高 的正向影響，而且知識分享自我效能則擁有最高的中介效果。這項研究結果提供了豐富 的學術洞見與行銷意涵。

The prevalence of the computer-mediated environment and the Internet have led to the emergence of social network sites. Social network sites have not only changed the way people communicate and share knowledge with one another, but have also created socialnomics and social commerce. Previous studies on social networks have focused on user behavior and mostly adopted an exploratory approach. In contrast, this article develops a holistic model that incorporates three facets of social capital (structural, cognitive, and relational) as determinants of users’ knowledge sharing behavior and examines the mediating roles of users’ psychological safety and knowledge sharing self-efficacy. The proposed structural equation model is empirically tested with survey data from 439 Facebook users in Taiwan. The results show that cognitive social capital exerts the strongest positive impact on Facebook users’ knowledge sharing behavior and that knowledge sharing self-efficacy indeed plays a mediating role. The findings provide important insights for both theory and practice.