An increasing number of organizations have installed enterprise social media (ESM) platforms to allow employees to collaborate, work independently, and to innovate more easily. While research has started to explain how such technologies can lead to improved collaboration and productivity, their role in assisting employees in innovation processes remains unclear. In our research-in-progress we examine the case of a global retail organization that adopted ESM for all employees with the view to foster employee-driven innovation. We report on our on-going data collection and analysis, in which we focus on the salient mechanisms and contingency factors why ESM under some conditions facilitates employee-driven innovation and why under some conditions it does not. We report on on-going data collection, data analysis strategies and emergent findings, and conclude with a brief outlook on our future research strategies. \ \ Keywords: Enterprise Social Media, social networks, employee-driven innovation, case study. \