We envision that the architectural space we inhabit will be a new form of interface between humans and online digital information. This paper discusses Ambient Displays: a new approach to interfacing people with online digital information. Ambient Displays present information within a space through subtle changes in light, sound, and movement, which can be processed in the background of awareness. We describe the design and implementation of two example Ambient Displays, the ambientROOM and Ambient Fixtures. Additionally, we discuss applications of Ambient Displays and propose theories of design of such interfaces based on our initial experiences.