XML
   - XML is the extensible markup language.
 
   - Unlike HTML, you define your own tag set in XML.
 
   - Tags in HTML include the paragraph, headers and
       list elements.
 
   - The less than and greater than sign make the
       tags.
 
   - In XML you need an end tag.  "< tag >  stuff < / tag >"
 
   - You can embed elements in other elements.
 
   - Like HTML, you can't cross brackets.
 
   - Like HTML, it doesn't really do anything;  there's no processing;
       neither XML or HTML are Turing Complete.
 
   - Tags can have attributes inside. They need to be quoted.