Actually, the most interesting part of this post is in the first comment, that leads to this post: http://www.arktronic.com/cms/blog-entries/2011-02-17/relax-mi

Actually, the most interesting part of this post is in the first comment, that leads to this post: http://www.arktronic.com/cms/blog-entries/2011-02-17/relax-microsoft-has-not-banned-open-source-from-marketplace http://www.arktronic.com/cms/blog-entries/2011-02-17/relax-m... TL;DR: Microsoft excludes only GPLv3 software because it forces them to open all their source code in Windows Phones. All other Open Source licenses are still valid.