XML is honestly the greatest and I'm not sure why it didn't take off. People sometimes ask me, "what impacted the humanity the most - electricity? antibiotics? combustion engines?" -- no, no, and no, it was XML. Everything can be expressed in XML, and basically everything can read and write XML. It's like the whole world could read and write the same files. Imagine what if those files included programs, that's what XSLT is, a program that's a file of the XML format that performs transformations between XML format and XML format. Wow - now everything can read and write your programming language! About 90% of it is usually around a capacity to use XML to document your XML to XML transforming XML code, and then the other 9% is boilerplate, 1% does the lifting. Brilliant. Imagine a more verbose java, for those of us who find java terse, it almost feels like assembly to me. XML is like the tower of babel that unites all of humanity and JSON is the devil that shattered that dream.