is the Microsoft Office monopoly more dangerous than Microsoft Windows monopoly?

Jakob Neilsen, usability nut, offers this interesting proposition:

“…the real platform these days is Office and that Microsoft’s monopoly at this new level is of more concern than what they do with Windows…”

To a degree, this is true. Most common business documents use the Microsoft Office formats (primarily Word, Excel, and Powerpoint). Regardless of whether you are using a Mac or a Windows PC (I realize that there are significant operating systems left out here), you can email Office documents to other (Microsoft sanctioned) platforms to your hearts content.