Jensen Harris has posted his first post in a series of, er, posts relating to the new Office UI.
"...the roots of the early Microsoft Office programs were rooted in the Mac and of course, the user interface reflected that. As the Mac's first and biggest provider of software (a title Microsoft still holds today), some of the UI decisions made in the original Macintosh were influenced by the needs of Microsoft's development teams. While the extent to which it is admitted this happened varies widely depending on the personal account, it is safe to say that the programs were developed with an intimate understanding of the system and vice versa. Certainly, the basic outline of Office's graphical user interface (especially the use of a top-level menu bar) has its roots in that first Macintosh version."