When I blogged my approval of Microsoft's covenant not to sue over usage of their XML based office document format(s) the actual covenant had not been posted. Now that it has, I'm not so certain it meets the need. The link above will take you to a ZDNet UK site with a comparison between the Microsoft covenant and the one Sun Microsystems is applying to their intellectual property in regard to the Open Document Format.
I'm still not sure the terms of Microsoft's covenant rules it out as not sufficiently open. There will have to be some clarification. Right now, the covenant resides only on a web site controlled by Microsoft and they can change the terms at any time. Once things are more firmly committed to, we can judge. I think MS will come around sufficiently to meet the standard for "openness" in this area. Stay tuned.