Generative design processes have been the focus of current architectural research and practice largely due to the exploration of the phenomenon of emergence within self-organisation, generative grammars and evolutionary techniques. These techniques have been informing participatory urban design modalities, which are investigated in this paper by critically reviewing theories, practices, and (software) applications that explore multiplayer online urban games, not only with respect to their capacity to facilitate online, trans-disciplinary, expert collaboration and user participation, but also to support the implementation of democratic ideals in design practice.