This paper examines the behavior of Facebook users, focusing on the reactions to published posts of official fan pages of professional sport teams. In particular, potential changes of the reactional behavior subject to the success of the team and to the media representation on the site are investigated. The reactional behavior was determined through the examination of the various emoticons which are available underneath every published post on Facebook; the media representation was assessed through a computerized semantic analysis of the investigated posts. It was assumed that both the success of a team as well as an affirmative media representation (i.e. positively worded posts) would correlate with a higher percentage of positive reactions of the followers due to an increased individual and collective self-esteem, while the team success should also relate to the total number of reactions. The combination of low success and affirmative media representation should be linked to fewer positive reactions likewise the connection between success and group cohesion. In total, 30 different fan pages with 32 published posts each were examined, using an event sampling method as well as a multi-level analysis. Results show that the success of a team correlates, as expected, with a higher percentage of positive fan reactions on Facebook, but that an affirmative media representation in itself as well as a high group cohesion (indicated by a smaller number of Facebook-fans) does not increase supporters responses. Subsequently it is discussed that while the success of a team might be the primary reason for increased fan reactions, other factors might be influential as well. The need for future studies to examine potential long-ranging trends and changes of supporters behavior based on team-related factors are shown.