So, some blogs are social media: Blogger, Blogspot, live journal are examples. The users of the site provide the content, have profiles and submissions, all that.

But some are not! Dev blogs for software projects and site update blogs are good examples of this. They may or may not have comments but it’s the proprietors of the websites providing the ordinary content.

Who provides the content, users or proprietors, is what makes it social media or not.