YML - Why a Markup Language?!
Any time a formal language is created for computing, a compromise has to be found: whether the language is perfect for the computer but terrible for the human or vice versa. XML is very good for the computer ;-)
Using XML for the reasons mentioned above, but for programming? "Why a Markup Language?!" was what I was shouting some time playing around with a code generator in XSLT. That gave the idea.