The widespread adoption and use of social media in almost every aspect of our daily lives may outpace existingempirical understandings. In organizations, social media are increasingly used by professional individualsand communities to support dynamic collaboration and knowledge sharing. While there is a growing amountof research on this subject, still little is known on how people use different kinds of social media in practice.That is, there is a need for an empirical understanding that addresses actual use practices of social mediawithin the formal boundaries of organizations. To this end, we report on results from a qualitative comparativestudy of the use of wikis at two global organizations. Our aim is to develop an empirical understandingof the enactment of structures and the ways by which people structure and organize their wiki use practicesby drawing on Orlikowski’s (2000) practice lens. The findings from the authors analysis suggest a number ofenacted structures that reflect diverse wiki use practices. The main contribution centers on developing threekey mechanisms that provide means for understanding the structuring of the use of technology.