"Extensibility · The “X” in XML stands for “Extensible” and that’s because anybody can invent an XML language. You could post a chunk of text on the Internet like so:
X311-J
"And you wouldn’t have to ask anyone’s permission to use the terms “tool”, “tier”, or “frobnosticate”, because of the extensibility.
"Of course, doing that isn’t very useful. Most people who use XML work with handy pre-cooked sets of tags like RSS or Atom or XHTML or ODF or OOXML, and leave the extensibility to the people who do the pre-cooking for us. Most times, you never actually see the XML.
"History · But back the era of XML’s predecessor SGML, and even somewhat into the XML era, there was this vision that everyone should go out and invent new XML languages to meet their own particular business requirements. I think that these days, most people have come around to the view that you shouldn’t do that."
