Microsoft offers a royalty-free license to the new Office UI

Jensen Harris drops a bombshell on his blog today. With certain understandable restrictions, Microsoft will issue a royalty-free perpetual license to any developer who wishes to use the new Ribbon UI in a product. You must agree to Microsoft license agreement (I have not had time to read the entire thing) and adhere to the 2007 Microsoft Office System User Interface Guidelines (PDF). Jensen writes:

For the last year or so, one of the questions I've been asked again and again has been: "Can I use the new Office user interface in my own product?" 

Well, I'm pleased to finally be able to definitively answer the question. Today, we're announcing a licensing program for the 2007 Microsoft Office system user interface which allows virtually anyone to obtain a royalty-free license to use the new Office UI in a software product, including the Ribbon, galleries, the Mini Toolbar, and the rest of the user interface. 

This is a smart move, IMO. By making the Ribbon available to independent developers, Microsoft succeeds not only in making the new UI more common but also prevents cheap knock-off ribbons from proliferating. I'm looking forward to seeing what the developer community does with this offering.