This is an excerpt taken from this article
http://ruudhein.com/data-portability
DATA EXIT STRATEGY
Planning, and testing, a Data Exit Strategy, is as important as your Backup Strategy: you don’t want to find out if it works or not by the time the rubber hits the road.
Before you commit to a tool, see what it exports how. Compare that end product to the value you hope to get from the tool; is what it exports of equal value as to what it contains, what you put it?
If not, how would you recuperate that value upon exit?
I think this makes a lot of sense in this day n age of software companies using proprietary data structures and unsustainable business models.