I just stumbled over this really funny
and interesting blog entry:
It's about Office 2007 trial versions,
which allow you to store your files only in OOXML, even clipboard
exchange with other applications seems to be disabled.
So when the 30 days trial period ends,
you have two "choices": Buy Office 2007 for being able to
access your own documents, or find some tool for converting your
documents from OOXML to some really open document format, like ODF.
Finding some tool sounds reasonable, but AFAIK there is no final version of any such tool available right now, so you might loose some formatting or even some data!
I especially enjoyed the sentence
“Choice is an optional extra, only available after purchase” :)
ODF is supported by different open
source and closed source products, for example
Sun StarOffice, OpenOffice.org, IBM Notes 8, KOffice, Google Docs & Spreadsheets and many more.
No risk to get locked into software
by one particular vendor!