The technology of communication devices, systems, services has changed over the years. There have been telegraph, telephone, radio, television, and a variety of others. The characteristics of each technology have dictated the behavioural model of the systems and the services available to users.
With the advent of the internet, systems have tended to emulate traditional models: bulletin boards, post (email), with the web being based on a well-known “request-response” model until relatively recently.
But, now, the gloves are coming off! People are building software-based communication services to provide whatever behavioural model they choose; consider, for example, Facebook, Twitter, FriendFeed and there will be many, many more.
So far, their matching of the models to any specific requirements has been very loose. They build something and then figure out what people use it for!
There is an opportunity to get serious now: to decide whatever experience we want users to have; to design it and build it. Then to iterate models based on live tracking of actual scenarios. This is potentially very big … and keep half an eye on “augmented reality”.