All the bits of identity that we claim or reject (for the rejected bits still cling to us), are pulled into a human shape by Lacan's mirror. We get an imago of the "I" that we now come to believe exists. Ah! Someone has even given this "I" a name. So, equipped with this ideal image and name, we procede into life's tempests. Which bits of identity we include in this image/name construct, which I will call analog-I, are determined in each "now" by feedback from interaction with others.
But sometimes stronger forces are at work within us, often related to residual emotional content from out childhood. This content is often raw and pre-verbal, coming from a time when we did not have the mental capacity to process it. How then does this content affect our analog-I? If it is strong enough, or if it receives outside encouragement, other self-images may develope. These at first have the same name as we do, but over time may become self-named, for example Stefani Joanne Angelina Germanotta became Lady Gaga. But not all alternate analog-I's become so powerful. For the most part, they exist as shadow people, emerging only when the environment is safe for them to do so.
In a virtual world such as Second Life, the bits of our identity can be broken out of their analog-I and shadow people shells more easily than in real life because their are more options and opportunities for us to really "build" ourself. Some people take a safe route and reproduce an idealized version of their real existence; others pick one of their shadow people that they have always wished to display, but for whaterer reason were unable to do so in real. Even those who experiment radically with image and name eventually find the form(s) with which they are most comfortable.
Lacan tells us that the core of identity itself is a falsehood. We are really all the bits of us, but the image we think we are and the name that attaches to that image can only hold a few of those bits. Therefore that analog-I, in whatever form we try to present it to others, is not really "us"--it is just a picture and a word. Perhaps Lacan was right, we can never experience the Real--all those bits of identity that make up a human being. But that should not keep us from experimenting!