1st step...why do I write?

I am on orkut, linkedin, facebook, and Twitter. I twit regularly (not daily though...), and a friend once asked me, 'why are you twitting? Is there anyone who is reading that scrap?' Well, I struggle for an answer after that, why do I twit? Why do I write? And, then one day I came across this quote, "The act of writing is the act of discovering what you believe, that's why to know more about you, you should write and write.." I was thinking of starting my own blog, but the question was what the blog should be all about? I do follow many blogs, some are to spread the knowledge, some are about their daily routine & thoughts. I thought to myself, I can not write about both these things and ask some one to read that, because neither am I expert in some field to spread the knowledge nor am I celebrity in any sense. So, the question remains, what should I write in my blog, if I start any?
Because, I could not find the answer to my friends question, today I have decided to write for me. This is my space, I will share my stories, my experience, and my thoughts... so, this is my 1st step, lets see how far I can travel. As the famous quote goes, 'the journey of thousand miles start with one step', so I have taken my 1st step now, lets see how the journey goes...