Here's the facts:

1. Many organizations, in particular governments, are beginning to mandate the use of open file formats.
2. A potential competitor to one of Microsoft's core product lines (read: profit center), OpenOffice.org, uses ISO open file formats; ODF, and is thus of some great interest to these government agencies.
3. Microsoft cannot afford to have its Office profit center undermined either by a competing product or by a competing, open standard like ODF.
4. Microsoft creates OOXML, a document standard so enormous and so riddled with proprietary references that it would be impossible for anyone not privy to Microsoft's older formats (which are not published) to actually produce their own OOXML-compliant product.
5. Microsoft then attempts to subvert the ISO by trying to buy votes. The purpose of this is to get OOXML ISO certification, so that when a government agency mandates an open document format, Microsoft can maneuver OOXML, which can only really be utilized by Microsoft Office, by trumpeting its "open" designation.

In short, OOXML is a rather elaborate scam, involving an unimplentable format, subverting the ISO and using it to maintain its all-important Office product line from meaningful competition.

Link.