During our session here at the NPR Social Media Advisory Group Jay Rosen just pointed out that in a mass media world the audience is atomised. They have no easy connection to each other. In a connected world the costs of them connecting to each other is trivial and this fundamentally changes the relationship between broadcasters and their audiences. He is talking about applying "open source wisdom" with his site NewAssignment.net which he described as "Organising people horizontally using the internet to contribute and collaborate".
You would expect me to say this but this truth applies just as much inside organsations. Thus far most comms activity has been top down, one to many and in terms of ROI expensive. With social computing tools inside the enterprise "Organising people horizontally using the internet to contribute and collaborate" becomes trivially easy and cheap.