A blog is a great place to post interesting, insightful and fun things. Or even boring things. It doesn’t really matter as long as you like doing it. I really enjoy reading my friends’ blogs. It has a different feel to it as opposed to reading a generalized feed on a social network. Typically, I tend to sift through the updates in my feed. I don’t really pay much attention to the items in my feed. That is not really a great experience. This wouldn’t be the case if everyone had their own personal blog.
The biggest thing that social networks fail to capture is the essence of a person. Even if, say, Facebook, allowed its users to customize their profiles completely, it’d still fail to display a person’s uniqueness, since, they all reside on the same domain.