It's obvious that not everyone is happy about Microsoft's most recent attempt to woo the open source community by releasing API details and offering them for use with a covenant "not to sue open source developers for development or non-commercial distribution of implementations of these protocols".
It isn't yet clear exactly what qualifies as "non-commercial distribution", but it's an interesting approach: Microsoft has always complained (sometimes unjustifiably) about the GPL. Now authors of open source products can use the newly-released information as long as they don't gain commercial benefit by doing so. This could be seen as opening up, or simply as a nice piece of spite. It will definitely result in the development of interoperable projects that will take market share away from Microsoft, leaving software dollars looking for other places to be spent.
I suspect that a lot of people will say that this doesn't go far enough, but it's a sea change in Microsoft's approach and has doubtless taken lots of internal discussion. If you develop a commercial product based on Microsoft's patented technologies then you will still need a license from them before you go to market. As long as you believe software patents are reasonable this is nothing to complain about.
Personally I have never thought software patents reasonable, but Microsoft are to be congratulated for trying to promote their technologies in a more open way. Let's hope this is just the first step to fully open standards, only twenty years too late.