For today's organisations to obtain competitive advantages, online corporate Communities of Practice (CoPs) are indispensable. However, often the majority of its participants does not post content; they lurk. We explore four different perspectives on why people lurk; that is free-riding, legitimate peripheral participation, microlearning, and knowledge sharing barriers, and analyses whether and why they are detrimental or fruitful for the knowledge management process. To gain insight in the reasons for people to lurk, we conducted a study comparing lurkers and active participants of an online corporate CoP in the light of the perspectives as presented above. First, the results of this study indicate that lurkers use the obtained knowledge on the job and therefore cannot simply be considered free-riders. Second, study results suggest that lurkers use lurking as a learning strategy, which confirms the microlearning hypothesis. Last, the results of this study indicate that knowledge sharing barriers can enhance lurking and might be detrimental for the knowledge management process.