By applying ethnographic method this study sought to explore how football’s mediatization is inviting the digital displacement of fan culture by social media-based communities. It also aimed to understand how contemporary football fans engage online as part of identifying themselves as supporters of a football club. This research was motivated by the global resonance of fandom which is due to the media becoming part of the experience of being a fan, resulting to the formation of transnational communities. The two-way online communication has enabled supporting from afar, forming digital fans. Liverpool FC’s Greek fans official group on Facebook was used as the case study for content analysis, along with in-depth interviews. The results have shown that social media have been the facilitators of football’s mediatization, digitalizing fan habits that used to be parts of the social life. Self-identification as a fan has taken a much more cosmopolitan outlook, which prioritizes participation. The dimensions of participation are though mediatized, resulting to highly engaged communities regardless of locality. To deal with the redefinition of fandom expression, this thesis has contributed with an end-result protype of a service addressing the process of doing digital fandom. As media technology develops, football’s mediatization will only exponentially increase and this study can offer insights to the better understanding of the different dimensions that digital fan culture adds to the sport.