RSS, SSE and CC

Preface: I’m asking a question, not making a claim in this post. Please read this accordingly.

This new SSE extension that Microsoft recently pushed out is very odd in one respect that I don’t understand. Some have voiced satisfaction that this RSS/OPML extension has been released under a Creative Commons license.

My reading of the license is that while the specification has been released under the license, your ability to implement the specification and write software based on it is not clarified by the use of CC. The license says that you can:

… copy, distribute, display, and perform the work

Is that my license to implement SSE?

Regarding the license, Microsoft says:

As to software implementations, Microsoft is not aware of any patent claims it owns or controls that would be necessarily infringed by a software implementation that conforms to the specification’s extensions.

It’s this part that matters, not the fact that it’s CC licensed. In fact, I don’t see any big benefit from licensing this using CC… do I want to be able to make derivative licenses? While I don’t think that it is harmful for people to do this, it strikes me that the emphasis has been placed on something that doesn’t really matter. The part that matters is the bit where Microsoft says what you can do with implementations based on the license, which is that they will offer a:

… royalty-free patent license on reasonable and non-discriminatory terms…

Hmm. Reasonable. Non-discriminatory. Hmm. Vague.

RSS 2.0 is in the same boat based on this interpretation:

RSS 2.0 is offered by the Berkman Center for Internet & Society at Harvard Law School under the terms of the Attribution/Share Alike Creative Commons license.

I just don’t know what that means in terms of my ability to implement RSS 2.0. It seems clear that I could create Phil’s Simple Summary format and base it on RSS 2.0, however.

For comparison, RSS 1.0 specifies this in the “Rights” part of the spec:

This copyright applies to the RDF Site Summary 1.0 Specification and accompanying documentation and does not extend to the RSS format itself.

That is clear: the license applies to the documentation, not anybody’s right to implement it.

Please set me straight:

When I write a spec for a format or API and release the documentation under a CC license, does it have any implications for someone’s ability to implement that format or API?

Update

: Contrast this non-clarity with the OASIS Open Document Format for Office Applications intellectual property information. That explicitly spells out the fact that you can make royalty-free implementations of the specification and that Sun and OASIS won’t enforce any of their applicable patents that may affect implementations.