Abstract During the last decade research groups as well as a number of commercial software developers have started to deploy embodied conversational characters in the user interface especially in those application areas where a close emulation of multimodal human-human communication is needed. Incarnations of such characters differ widely in type and amount of embodiment - starting from simplistic cartoon-style 2D representations of faces, fully embodied virtual humans in 3D virtual worlds to physically embodied androids co-habiting the user’s real world. Despite of their variety, most of these characters have one thing in common: In order to enter the user’s physical world, they need to be physical themselves. My talk focuses on challenges that arise when embedding synthetic conversational agents in the user’s physical world. Following [4], we may classify the contact between synthetic and human agents according to a ”virtuality continuum” (see Fig. 1). At one extreme, we ...