Blogs are important because, unlike old medium such as television, the user owns the content. Their is an old saying in the television, he who controls the pipeline controls the content. This is tired and true, especially for news media such as CNN, MSNBC, and FOXNEWS. Since users own their blogs, they are free to post content they see as fit. In other words you control the content that you allow the world to see.
Blogging also adds other benefits for the user.
You'll become a better writer. As long as you constantly post things, you'll notice that stringing sentences together become easier. Almost fluid.
You’ll become a better thinker. Since the process of writing is putting thoughts on paper, the same applies with typing words on a computer. The more you do it, the easier words flow into your head as you type out what you want to say.
On top of that blogging is like your personal journal for the world to see, you'll gain confidence as you write what you think knowing its open for the world to see, and above all else it's free.