One of the key themes in knowledge management is the role of information systems designed to facilitate the sharing and reuse of knowledge – often referred to as knowledge management systems (KMS). However, the intended users of such systems are often reluctant to use them, and implementation failures are common. While prior research offers important insights into the problems and practices of IS implementation in general, little is known about the special problems involved in implementing KMS. This study seeks to better understand the process of KMS implementation and establish a theoretical framework for examining the underlying dynamics of adoption and use. We suggest that efforts to implement KMS need to be sensitive to the social interactions and the collective sensemaking of the intended users if they are to be successful. In making this argument, we build on recent research within the field of network economics and highlight the concept of network effects. Using an exploratory case study as an illustration, we argue that KMS exhibit strong network effects and that these create positive feedback loops that complicate the implementation process. Our conclusion is that the concept of network effects offers an interesting and useful analytic perspective for understanding the implementation of KMS in organizations. Implications of using this theoretical lens for both research and practice are discussed.