Wow, there's some really deep thinking going on in this thread..
Myself, I have yet to really create a definite online identity. I've gone by Chimera and Pomola on online art communities, as well as a pen name (which has a basis on my real name). 'The Lizard Queen' is a pretty goofy alias that I've taken to using around the net too, heck, it was inspired by a quote from a Simpsons episode. I've always had an urge to establish an online identity, but I've never been sure whether to pursue it.
In real life, I'm pretty quiet, and often overlooked. I'm just sorta...there. It can definitely get frustrating. As an artist, I often vent through my characters and art. I daydream alot too, which is something that I've been trying to control since I could see it getting away on me (reality should be a priority). It's kinda interesting though, looking back at the characters that I created as a fourteen year old versus the ones that I have kicking around now. It demonstrates that they definitely reflect my thoughts, feelings, interests and overall maturity.
I definitely don't confuse them with the real me. But they are kinda fun to have around, and I have to admit that on the bad days, I kinda wish I could wreck havoc with them. Not particularly sure if I'm making any degree of sense. That's probably just because honestly, I'm going through a stage of trying to figure myself out. Who knows if I'll ever actually succeed. At the very least, It's reassuring to know that my relationship with God is a constant presence in my frequently befuddled mind.
Also, it really doesn't help that I've met about...at least twenty people with the same name as me! It's a nice name and all, but I've hit the point were I don't answer to it, even when people are actually trying to get my attention. Really, I'm not sure that it's possible to define a person by their name, I don't feel that my name fully describes me at all.