Why blog?

I asked a friend to explain to me why I would want to have a blog. He replied with this- "It's a place to vent and rant and say what you want semi-anonymously. I have too many opinions. One day my wife told me I needed to get a blog."

So here I am. My spouse isn't sure what a blog is. But sometimes it's nice to just write out one's thoughts and let them sail.