This paper describes the goal, design approach and specification, and preliminary use test of a use-aware ambient media called Coralog. Coralog is a widget which detects the duration of a user's computer idle time (i.e. having the computer on without active usage) and communicates the energy consumption behavior through the visualization of the health of coral reefs. By occasionally consulting the non-intrusive widget, users have immediate feedback of the effect their behaviors have on otherwise distant, but important ecosystems. Therefore, the goal of this application is to make the public become aware of the connection between their everyday activities and global climate change, which will educate them about the formerly unseen effects that their actions may have and potentially lead to a sustainable living. Keywords Eco-visualization, Ambient Media, Awareness, Sustainability, Conservation Behavior, Persuasion ACM Classification Keywords H5.m. Information interfaces and present...