Why blog?

Why do people blog? I was wondering since some time ago.
I read random blogs everyday and find myself so interested in the idea, and excited to read from others.Then I decided to blog, f I asked myself, "why shall I blog?"

I thought about two points here:
1- I write about myself for myself, I need to express my thought, my feelings, my opinion in the form of words.. it relieves!In this case, why don't I write them offline, save and keep them on my own machine?
2- I want to share my day events, my thoughts, my feelings with others, I wanna them to be read, for the sake of sharing.In this case, mmmm, not everything will be said, not everything will be expressed indeed, so what?

I am confused .. really confused about it .. But I want to blog, that is what I know now.Sometimes, I need to narrate events or situations and I find no one at that moment to tell, or when I find, I skip some details which are important to me, but I guess the listener wouldn't be interested.So, here it is a way, to tell all out, to narrate all, it is my right now to say all the details, I won't bore my listener.

But now, when I am talking, whom shall I address?Me? You? and who are you?The Unknown? Can't determine, will just begin and let's see how it will go.