Many of us are curious about Second Life. The online environment defies explanation because it fits no existing models – it is an online experience that largely allows the users to shape the environment to their own interests. Educational bloggers (e.g., David Warlick) are fond of speculating on the potential of the environment for educators and learners.
Philip Rosedale is one of the founders and has some interesting things to say. He offers a perspective on this environment from the perspective of a developer. If you are interested in an overview of how it works, the video demonstration is very interesting. I understand this as an example of object oriented programming – create an object, program it to have certain capabilities. As millions of objects are put in place, interesting and unanticipated (emergent is the way Rosedale describes it) things begin to happen. Emergence is the key.