ClearBoard is designed to integrate interpersonal space and shared workspace seamlessly. A design goal of ClearBoard is to allow a pair of users to shift easily between interpersonal space and shared workspace using familiar everyday cues such as the partner's gestures, head movements, eye contact, and gaze direction.
The key metaphor of ClearBoard design is "talking through and drawing on a big transparent glass board." ClearBoard requires less eye and head movement to switch focus between the drawing surface and the partner's face than is needed in either the whiteboard or the desktop environment.
We found ClearBoard provides the capability we call "gaze awareness": the ability to monitor the direction of a partner's gaze and thus his or her focus of attention. A ClearBoard user can tell which screen objects the partner is gazing at during a conversation more easily and precisely than is possible in an ordinary meeting environment with a whiteboard.
This project was conducted when Ishii was working for NTT Human Interface Laboratories, Japan.
(Source: http://tangible.media.mit.edu/projects/ClearBoard/)