An interesting post, especially in the context of my own "CMS." I've run into different hurdles, partially because my site isn't "static," per se. The most interesting bit here is the bit about YAML as a data format. I don't have much expirience with it, but have seen it used in many static site generators...this was exactly why I didn't use YAML, and instead settled on raw JSON stores. It struck me as strange that there was a type of markup used almost, as far as I could tell, just for static site generators. Well, that and JSON is easier to parse in PHP.