This guide is optimized for the Second Life Viewer and also for PC.
Second Life (SL), according to its website, is the "Internet's largest user created, 3-D virtual world community." It is a place to "connect, work and explore, to be different, free yourself and your mind". Virtually everything in Second Life is created by users and behind every avatar is a real person. It is not a game, although users can and have created games for Second Life.
This brief video explores a tiny portion of the possibilities of Second Life.