Networked Surfaces are surfaces such as desks which provide network connectivity to specially augmented devices, for example handheld computers. When the devices are physically placed on top of the surface, they can connect to different kinds of services – mainly, but not exclusively to send and receive data. This paper discusses challenges in implementing Networked Surfaces, paying particular attention to data flow issues, focusing on how the various software and hardware entities comprising the Surface interact to transport data to and from objects.