Social Media and Identity

What aspects shape our identity?  Our age?  Our gender?  Our job?  Psychologists, sociologists and the neighbor across the street ponder this question daily.  But what is identity in a Web 2.0 world?  How is it different or similar to the personal understanding of self faced by a multitude of previous generations?

Descartes inquired about his own existence with "I think, therefore I am" but is this maxim enough in a social media-fueled life?  Maybe we exist with a multiplicity of selves, like the masks worn by actors in a play or movie.  Social media research suggests we are often kinder in a mediated world than we are in the physical world.  Should this information surprise us?  We are closer to in connection to anyone in the world than we have ever been, with perhaps only four degress of seperation from each other.  Are the masks of kindness shown in a net world more than an organic world? Does the net world also construct the multiple characters in our self, who are in search of an author?  Certainly, we can use a different name in our chat or gaming experiences.  We do not need to be who we are in our Twitter universe.  Even in this blog, I list myself as Dr. McCoy, not Dave McCoy.  Can these be two different people, or two different selves, occupying the same body?