In order to promote the ribbon design as a replacement for menus and toolbars, Microsoft has decided to license the Office 2007 User Interface including the new "ribbon paradigm". One of the primary reasons is to promote a consistent look and feel across all Windows applications that want to use the ribbon paradigm.
What made the menu and toolbar paradigm so effective is that it is familiar to all users. No matter what application one used, the menus and toolbars essentially worked the same. In order for the ribbon paradigm to be effective, it needs to be just as consistent and ubiquitous.
Currently the only way for developers to use the ribbon paradigm is to hand roll their own version. Microsoft fears that this will result in several inconsistent variants, so they have decided to share the user interface by publishing a publish design guidelines for developers.
The guidelines will require a license agreement, though it is royalty free. Any application, even ones not running on Windows will be able to use the ribbon paradigm without fear of IP lawsuits. The exception is applications that directly compete with the core Office products, namely Microsoft Word, Excel, PowerPoint, Outlook, and Access.
Impressions from the Channel 9 interview, suggest that Microsoft isn't really concerned about the ribbon paradigm as a revenue source. Rather, they want to take over from Apple as the thought leaders for the next generation of user interfaces. Expecting that other companies are going to copy the ribbon design anyways, and that bad copies will hurt the reputation of Microsoft Office, they decided the best course of action is to just make it easy to copy it the right way.
When asked if developers can implement ribbon-like interfaces that work differently but have the same underlying concept, Microsoft has said no. Microsoft has never before been this serious about enforcing this level of consistency before. Unlike past guidelines, mandatory requirements are legally mandatory according to the license agreement. While they are there specifically to ensure a minimum level of user experience, some developers are certain to dislike the idea of being forced to abide by the guidelines.
To reiterate, this license agreement does have teeth. If Microsoft finds a company not in compliance with the guidelines, they will be given the latter of 6 months or their next release to correct the issue.
Microsoft will not be directly providing the controls needed to fulfill the guidelines. They are working with control vendors to fill this gap in the offering. A list of vendors is not currently available.