Why do we blog?

I am getting really annoyed with the concept of blogging(besides the fact that I am now blogging about not liking to blog).

I just took down a post about a topic I felt was a little too personal, but when I posted it, it felt good, a heavy burden was lifted. But then, later I felt 'What the heck, that's too personal to be posted on the web'.

So what is it that makes blogging to mind controlling that it makes us posts things which we know could be damaging to us one way or another...

I'm sure most of you have no idea what I am talking about.. Do you?