The purpose of this thesis is to delineate important issues that sociable designers should consider when they develop structures intended to encourage social interaction. In doing so, i address both theoretical and computational contributions to this area of research. While i sketch a conceptual model for addressing these issues, the prototypes that are discussed reveal the challenges that we, as researchers and designers, must face. Rather than providing solutions, they expose the weaknesses in this area of research and suggest paths for future research. Explicitly structuring a system for social interaction requires overcoming many obstacles, as.