Blogging.

So, why do people blog? To rant, vent, to let it all out? What audience is everyone writing to? I myself, am not sure who I'm writing to. I might just be looking for answers to all this. I am new at all this blogging, and I've always wondered how some people are comfortable with spilling everything about themselves onto a blog. I'm tempted to try it out just to see how it feels, but I know I'll never get around to it.. One last question: Any critique for my blog layout?