Microsoft actually did not want to open the .doc format. I believe they were forced to do it.
http://en.wikipedia.org/wiki/Microsoft_Open_Specification_Pr...
I even checked the references, the MS page adds nothing to wikipedia's info in this matter
http://www.microsoft.com/openspecifications/en/us/programs/o...
It got us windows without media player (which nobody used), the browser ballot (which everyone endured) and a requirement that all their server protocols be documented sufficiently for competitors to implement the same service (which we all benefited from to a large degree). http://europa.eu/rapid/press-release_MEMO-04-70_en.htm?local...
[1] http://www.reuters.com/article/2008/05/22/us-eu-microsoft-id...
[2] http://www.infoworld.com/d/open-source-software/how-microsof...