As We May Communicate challenges the metaphor of the workspace (the desktop) as the way we work with computers: "Imagine that instead of seeing a quaint desktop when using a computer that we see a portal into a world of animate senders and receivers of information: avatars for agents, programs, operating systems, distributed systems, and, of course, other humans. Ideally, we could exchange and distribute information with a natural language system, handwriting recognition, or more traditional input systems. When we wish to gain information about a computer, software, or another person, we communicate directly with the representation for that object. [...] As in a conversation, we could be simply introduced to a communicative entity at first, but over time we could gradually be given a more complete picture of exactly what 'it' is and what "it" can do. Instead of overwhelming users with a dizzying array of unfamiliar features and commands, a communicative entity could gradually ease a user into a more comfortable relationship with itself".

In the communication space model, documents become collaborative artifacts created by users (who are human or software). Also touched on is the need for public and private selves. I'm not convinced, but it's good exercise.