In the age of the digital society, online fandom communities are becoming popular groups of young urban cultural enthusiasts in cyberspace. The aim of this study is to examine the cultural identity of these groups from the perspective of Cultural Studies. It used virtual ethnography as a methodology to examine the online fandom community "The Mortal Instruments Indonesia". In addition to the analysis of conversational texts, it also employed offline interviews of 43 participants and two focus group discussions. The study found that the identity constructed by urban youths as part of digital fandoms was fragmented into two subculture groups. The first was a group of fans consuming the popular culture in which they were interested with a deep emotional attachment, and developing fiction comprised of settings, storylines, and imaginary characters from it; the second was a group of fans categorized as the critics of the texts of popular culture who had an adequate level of media literacy for this purpose. Additionally, they were multi fandoms who were also fans of other popular cultures. This study proves that the youths' interest in global popular culture is not only due to the purpose of pleasure, but also because of their role as active prosumers, producers who create both cultural texts and paratexts which descend from their creativity.