I think the word you are looking for here is 'extend'... as in 'extending the format until only MS software can read it' :)
This is something which usually forms part of microsofts fall back strategy and which will be in everyones interest to fight against.
For those that didn't pay much attention in the 80s, 90's and nagthies, the microsoft fallback strategy is:
1. Embrace (java, html, and now ODF)
2. Extend (extra bits added in which only microsoft software can save/read.. still compatible with other software (for a given value) mind you)
3. Extinguish (leverage the extra extended bits to hinder/disadvantage/make life difficult for/destroy the competition)
oh, what do you know.. there's a wikipedia article :)
http://en.wikipedia.org/wiki/Embrace,_extend_and_extinguish
Biting the hand that feeds IT
