How to design XML to have broad utility and yet also enable efficient application processing?

Hi Folks,

Liam Quin wrote:

	XML frees your information from being 
	optimized for, and specific to, any one 
	program.

An obvious question arises:
	
	What is the right way to design XML?

I believe the answer is:

	Design XML so that it reflects (models) 
	the real world.

But real-world designs (models) may not be well-suited to efficient application processing. A second question arises:

	How do we design XML to have broad
	utility while still enabling efficient 
	application processing?

I believe the answer is:

	Each application should transform the
	XML into a form that enables the
	application to process it efficiently.	

Do you agree with this?

Is there anything else you would add?

/Roger