It's never occured to me that blogs are not social media. Social media sites, at their simplest, can be described as any that allow you to share, or as we are fond of saying, "join the conversation". When you blog, you become part of the "blogosphere" which is a community no matter how you look at it. Also, you create a profile when you blog, which often includes the same kinds of information you feature on Facebook or Twitter. And if Twitter, which is described as "micro-blogging" is social media, then how are blogs not?
Besides, Wikipedia says blogs are social media. Who's going to argue with that?
In short, blogs are a great way to get your information out and express yourself to those you have a connection with. So, for me, it's rather narrow minded to think of blogs as outside the realm of social media.