Massively Multiplayer Online Games and VirtualWorlds are among the most popular applications on the Internet. As player numbers increase, the limits of the currently dominant client/server architecture are becoming obvious. To overcome those limits, the research community has developed protocols for these applications based on peer-to-peer technologies. However, no consensus has been found yet on how the potential of peer-to-peer can be optimally used for these applications. In this paper, we compare and evaluate three classes of proposed architectures that within themselves share common design principles. One representative protocol of each class is examined in greater detail. The performance of these protocols is then evaluated in different scenarios in a series of simulations. We show, that the architecture with the best performance in message delay is the one relying on mutual notication for detecting new neighbors and on direct connections to all neighbors for exchanging event messages. Furthermore, this architecture is still competitive regarding the required bandwidth.