Since our publication of the FeedSync 1.0 specification earlier this month, a few people have asked me questions about the licensing terms in the spec.  

So, today, we wanted to make our intent as clear as possible by covering the FeedSync specification under the Microsoft Open Specification Promise.  By doing this, we are confirming that anyone can implement the FeedSync specification for free.

The specification itself remains under the same Creative Commons copyright license, as described in Section 6 of the spec. What this means, roughly, is that if you want to create a derivative version of the specification, you're welcome to do so as long as you properly attribute the original spec, and you provide your work under the same license.  Full details are here: http://creativecommons.org/licenses/by-sa/3.0.

The Open Specification Promise is intended for developers who want to implement the spec. As is our general practice (and general practice within the industry), we have filed patents on innovations relating to FeedSync.  As the spec has stated since the original version, it has always been our intent to enable broad royalty-free use of the specification. We are now covering the FeedSync specification under the Open Specification Promise to enable that use in a simple way, and to reassure you that you're welcome to implement the specification for free, easily, now and forever.

The Open Specification Promise is the same royalty-free patent promise that Microsoft has used for the WS-* and other specifications.  One of the benefits is simplicity: the promise is very clear that other than reading and agreeing with the terms, you don't need to sign it or have any interaction with Microsoft in order to benefit from it.  In other words, It Just Works.  We developed the promise based on feedback from customers and the open source community. You can find more information about it at http://www.microsoft.com/interop/osp/default.mspx, and see specific community feedback here.

--Steven