CoSync builds the ability to create and act jointly into mobile devices. This mirrors the way we as a society act both individually and in concert. CoSync device ecology combines multiple stand-alone devices and controls them opportunistically as if they are one distributed, or diffuse, device at the user�s fingertips. CoSync includes a programming interface that allows time-synchronized coordination at a granularity that will permit watching a movie on one device and hearing the sound from another. The open API encourages an ever-growing set of such finely coordinated applications.