Knowledge Management Systems have been actively promoted for decades within organizations but have frequently failed to be used. Recently, deployments of enterprise social networking platforms used for knowledge management have become commonplace. These platforms help harness the knowledge of workers by serving as repositories of knowledge as well as directories of knowledge holders. As with prior systems, a key challenge faced by organizations is how to initiate and maintain a minimum level of knowledge contributions. Existing IS literature on the causes of knowledge contributions shows conflicting findings. This work suggests that human factors, social networking platform technology and community factors, and environments internal to organizations are each necessary for understanding the causes of knowledge contributions. This work presents three studies that: 1) develop a framework for the analysis of knowledge contributions via social networking platforms, 2) demonstrate the impacts of different incentives and managerial controls, and 3) extend our understanding of group-level influences within organizations. With a better understanding of what drives knowledge contributions in a social networking platform used in organizations, we are better prepared as researchers to engage in research that reduces inconsistencies in the knowledge management literature, as well as more able to assist practitioners in designing optimal conditions for knowledge sharing within organizations.