In this paper we reflect on our long-term experiences of developing, deploying and supporting an experimental digital signage system. Existing public display systems almost always feature a single point of control that is responsible for scheduling content for presentation on the network and provide sophisticated mechanisms for controlling play-out timing and relative ordering. Our experiences suggest that such complex feature-sets are unnecessary in many cases and, indeed, may be counter productive in signage systems. We describe an alternative, simple, set of tools for encouraging widespread use of signage systems based on a shared system of `content channels' from content providers and display owners. Our system has been in continuous use for approximately 3 years and we reflect and draw lessons from how our user community has adopted and used the public display network. We believe that these reflections will be of benefit to future developers of ubiquitous display networks.