living vicariously through your online identity

It is common knowledge that people act differently online than in their everyday physical lives. From the comfort of a somewhat anonymous computer screen, the ugly duckling is a swan, the shy boy is a ladies man, relatively unknowns are infamous, and some men are women (?). Social networking sites have only contributed more to this phenomena. Is this healthy?

Are we living vicariously through these online profiles? Are we "trying out" who we *could* be with our lives, while not affecting those in our actual lives? Or will these online masks, these pretend lives, eventually catch up with our real lives?