Why OOXML is Like Internet Explorer

So let's get this straight:

What got really interesting was when Yusseri raised the issue of OOXML and why didn't Microsoft just work on ODF in collaboration instead of creating a new, bloated standard. Bill [Hilf]'s answer was quite surprising, as he clarified that the file format (OOXML) was a part of the software and that OOXML and the software (MS Office) are quite inseparable. Ergo, OOXML is an integral and inseparable part of MS Office. That's why they could not adopt ODF as the file format for subsequent versions of MS Office.

Oh, I see. As in Internet Explorer is part of Windows, and quite inseparable - apart from the version of Internet Explorer that came in the Windows Plus! box to add on to the very first version of Windows 95 that was released without Internet Explorer.

All makes sense now.