[model] section 3.2.4 Metadata

Folks, 

I am going to start where i left off on the model..

Section 3.2.4 is a readability nightmare. Its one of those texts i kept
reading and re-reading again to make sure i understood the point.
It has two main content grasps:
a) What and how metadata can slice bread
b) Forces metadata definition and usage

May i recommend we move #a type text to an appendix? This would cut down
on the text and get to the point quicker.
In regards to #b i dont see some of the definitions really captured in
the schema (on page 75 in my printout). Of course this could be my
mis-interpretation after being fatigued and put to sleep reading 3.2.4

If theres agreement i will capture this in the tracker.

cheers,
jamal