From Computing Machinery to Interaction Design is an article by Terry Winograd that appeared in Beyond Calculation: The Next Fifty Years of Computing. In it he points out how we have gone from computing as calculation to computing as communication and media.
Winograd wants us to think about habitat rather than just the human computer interface. This sounds like my theory of interactivity.
“The traditional idea of “interface” implies that we are focusing on two entities, the person and the machine, and on the space that lies between them. But beyond the interface, we operate in an “interspace” that is inhabited by multiple people, workstations, servers, and other devices in a complex web of interactions. In designing new systems and applications, we are not simply providing better tools for working with objects in a previously existing world. We are creating new worlds. Computer systems and software are becoming media for the creation of virtualities: the worlds in which users of the software perceive, act, and respond to experiences.”