The recent expansion of new technologies offers many opportunities for brand building. This paper adds to the extant literature by investigating the determinants of the success of brand social network websites (BSN) indicated by the user’s loyalty towards the BSN. Using an online survey for sports fans and Facebook users we demonstrate that consumer-identification with BSN users, consumer-BSN identification, and satisfaction with a BSN significantly influences loyalty towards the BSN. It is confirmed that these relationships are moderated by the perceived level of a brand’s investment into the relationship.