Massively Multiplayer Online Games (MMOGs) are becoming increasingly popular in recent years. Traditional Client/Server architectures of MMOGs exhibit different issues in scalability, reliability, and responsiveness, as well as involve high cost for adding new servers when demand increases. The fast response time, support of large and growing number of players, and low cost are extremely important considerations when designing and developing a successful MMOG The underlying infrastructure of the game plays a substantial part in meeting these conditions. P2P architecture provides considerable support for scalability of MMOGs. It also achieves good response times by direct connections between players and reducing the interaction with a server. This paper reviews recent solutions for Peer-to-Peer MMOGs, to advocate this architecture as an answer to MMOG design and deployment problems facilitating scalability, communication with a focus on load balancing.