There are two main dimensions of virtual pseudonymity. The first is keeping one's human identity secret from the virtual community. Most of the benefits of virtual identity stem from this aspect of pseudonymity, because you can recreate yourself at will, free of any preconceptions based upon age, social status, gender, etc. To each their own, but I think that those who totally conflate their avatar and human identities are missing a great opportunity to push the boundaries of their self-conception.
The second aspect of virtual pseudonymity is keeping virtual identity from one's human circle of colleagues, friends and family. Although this sometimes is a response to a genuine threat to a career or a relationship, I think it mostly stems from either embarrassment about being one of those Second Life freaks, or simply not wanting to explain the unexplainable to the uninitiated. I get that. I really do. But I think that to fully reap the positive benefits of one's avatarian dimension, you have to claim it within your mundane human world as well.
Every avatar has a human counterpart. That's boring. But most humans do not have an active virtual identity. That's something worth sharing.