To quote Sean Lyndersay, of the Microsoft RSS team:
From the beginning we have sought an open and reasonable relationship with the RSS community. As one example, we have published various RSS and Atom extensions under a Creative Commons license. These specifications provide proof of our commitment to offer our contributions to the community and evidence of our efforts to advance the technology. We honestly hope that our work brings benefit to all feed publishers, developers and users, and we've been happy with the response we have received from the community so far.