Why does LibreOffice offer to read, edit and save documents in OOXML?
Just like OpenOffice.org, LibreOffice lets its users handle documents in the format used by Microsoft Office 2007 and 2010. It is important to understand that these formats, also called OOXML are in fact somewhat different from the ISO standard bearing the same name; in fact it is unclear whether anyone is able to implement the ISO standard.
To avoid confusion, we will refer to the Microsoft formats produced by Microsoft Office as Microsoft Open XML (MOX) hereafter. To enable data interchange, LibreOffice and OpenOffice.org before it, has traditionally engaged with the reality of a world filled with data in many, less than ideal formats. Our users are used to exchanging data bi-directionally between many proprietary formats, and their Free Software equivalents. Indeed there are few choices for a non-dominant player to deliberately shun inter-operating, and remain relevant.