OOXML as a response
James D. Mason says:
I spent 22 years as the chairman of what is now ISO/IEC JTC1/SC34. SC34 is the committee that standardized SGML in the 1980s and now is responsible for both ODF, supported by many open-source products, and OOXML, the XML released by Microsoft in response to ODF. Neither ODF nor OOXML has anything to do with ODA/ODIF, which have been dormant since the turn of the current century but were still under development in the 1990s in a committee that was parallel to the one that became SC34.
Our past analysis: OOXML is a response. Thank you very much for the confirmation. Stronger language from Mason found in this article.