Microsoft has announced its intention to license the Office 2007 “ribbon” user interface here.

Before signing up for this you should consider the implications carefully. Here are the key points as I see them:

Q. Who is allowed to license the UI?

A. Anyone whose products do not compete with Microsoft Office.

Q. What does it cost?

A. Nothing. You just have to click-through an online license agreement.

Q. What do I get if I sign up?

A. You get a detailed set of guidelines describing how the UI should work. You do NOT get any common controls or other software to help you implement the guidelines.

Q. Is there any downside to the license?

A. If you sign the agreement and then do not follow the guidelines to Microsoft’s satisfaction, MICROSOFT PROMISES TO SUE YOU!!!

Q. Even if I don’t sign the agreement, what is to keep me from just copying any elements of the Office UI that I like?

A. As far as I can see, nothing. (Remember I am not a lawyer.) A series of Federal cases in the late 1980s and early 1990s (ironically including one in which Apple sued Microsoft for copying their UI) established that copyright cannot be used to protect general UI elements like menus and toolbars.

It is possible that Microsoft has applied for patents on some aspects of the Office UI, but if so the patent applications should be public and no one seems to have noticed them. In any case unless and until the patents are actually granted they cannot be enforced.

UPDATE: Eric Sink has more thoughts on the matter: Microsoft Admiration.