A few years ago, a greybeard of my acquaintance quipped that blogs are this generation's unix shell.

My main nitpick would be that I see a standard blog as requiring a comments facility. Inbuilt, I don't count disqus as having reached the minimum feature level.

I'm also wary of flat file fetishism. Where data is strictly hierarchical and there is only one pattern of access, YAML would suit fine.

In blogs you pretty get into not-hierarchical-really stuff pretty quickly. As soon as the first per-tag or per-author archive page is added, for instance.