The original plan:
- XML (a lightweight SGML) 1998
- generic markup
 
  - validation
 
  
 
  - XLink / XPointer (lightweight HyTime) 2002
- stand-off links
 
  - n-way linking
 
  - structure-based addressing
 
  
 
  - XSL (lightweight DSSSL) 1999, 2001
- structure-based formatting and rendering
 
  - tree transformations
 
  - flow objects
 
  
 
  - XML applications / XML-based languages (SMIL, XHTML, MathML, ...)
 
  
An early addition: XML Namespaces 1.0.