In this study, the authors propose to discuss scalability challenges posed by Massively Multiplayer Online Game (MMOG) scenarios, while outlining issues specific to the context of online interactive experiences and game genres. These scalability issues concern: game simulation, content distribution, communication and coordination, and structural scalability. The authors present a critical review of approaches to known issues and outline research goals for an integrated scalability approach, to achieve a balanced, general purpose design, for MMOG infrastructure. Keywords Massively Multiplayer Online Game (MMOG), Scalability, system design, system architecture