There have been various claims that enterprise social networking sites (ESN) might improve business effectiveness and performance. Nevertheless, many of the initiatives supported by ESNs have failed. This paper argues that divergent perceptions about ESNs across the different levels of the organization may explain failures in ESNs’ design and implementation. Using an extended version of the Technological Frames of Reference framework (Orlikowski & Gash, 1994), this paper reports on a study that analyzed employee’s perceptions about an ESN within a software engineering firm. It was found that significant divergent perceptions in the organization led to a social order that discouraged employees to create and share knowledge through the ESN. This paper highlights the importance of aligning top management perceptions about the ESN with its actual scope. It also highlights the relevance of aligning perceptions about the ESN across the different levels of the organization. This paper proposes extending the original Technological Frames of Reference framework in order to better understand people’s perceptions about technologies that support knowledge management systems. It also proposes an explanatory model for understanding how people’s perceptions about a corporate social networking site impact on its usage.