There's a vast amount of data in the world
Most of that data is only implicitly structured
Every program needs an independent set of input routines
Computer programs need structured data
Adding markup is expensive and slow
Invisible Markup gives the best of both worlds:
Once upon a time, all HTML contained layout elements.
CSS extracted that presentation, allowing HTML files to be semantic and presentation-free.
CSS described the presentation of documents.
Furthermore, CSS files allowed a whole class of documents to be presented in the same way.
ixml is like that, except for markup
ixml describes the structure of (textual) documents, and allows the documents to be markup-free.
Furthermore, the ixml files can describe a whole class of documents.