Who I am is simple. I am no one, I am everyone. I exist, and I don't. I am simply another iteration of what you see everyday.
I am no different than the others that you interact with through the screen, I just chose another avenue of expression.
You cannot see or touch me but you read my thoughts and form your own body to put me in. In a way, that's how you see me.
To you, that's who I am. The only identifying factor of me is that I am a man on the internet, the rest is up to you.