This study is an attempt to discover how fans of certain bands interact and create shared identities. It is an investigation of what being a fan is, what the function of being a fan is and how fans themselves express this. Through an exploration of different theories regarding the concept of identity and how it relates to music, including theories of both sociological and psychological identity, the investigation leads into a discursive analysis of how the fans of two different bands - The Rolling Stones and One Direction – communicate on each bands’ respective Facebook – fan page. The analysis was conducted through the use of Membership Categorization Analysis (MCA) and ethnomethodological theory. MCA is the study of how people use categorization to create a sense of coherence and consistency in their daily life, which entails applying categories to themselves and other people in and through talk. Membership Categorization Devices (MCD) are used to sort categories into coherent systems through different rules of application such as Category Bound Activities (CBA). The two main MCD’s in this study were “fan of The Rolling Stones” and “fan of One Direction” to which certain CBA’s and categorical patterns were found. The results showed that, in order to be a fan, one is supposed to act and speak in certain ways, which can be related to certain themes such as “love”, “dedication”, “excitement” and “nostalgia”. There was found to be differences in the use of language between fans of the two bands; the fans of One Direction made heavy use of juvenile language and displayed an intensely emotional relationship to the band and its members, whereas fans of The Rolling Stones had a more varied and mature language and tended to show more individuality in their responses. Despite these differences the fans seemed to use the music for a similar purpose; to create a shared identity which is expressed in the different categories, CBA’s and MCD’s they both use and carry forward. The shared identities of the fans of the two groups should consequently be viewed as social processes constituted by all these aspects and actions rather than a fixed entity. This thesis should be considered as a kind of pilot project attempting to uncover how these social processes function in an online environment, and discuss related theories and methods which could potentially lead to a more elaborate and extended investigation.