Windows Phone Apps and GPL

Various news stories have appeared lately about the eligibility of GPL and other copyleft licenses for use on apps in the Windows Marketplace for Mobile (which carries apps for Windows Mobile phones).  The Application Provider Agreement containing terms excluding copyleft licensed material from apps has been in place for months, but the press has only recently turned its attention to the issue.  The relevant terms disallow inclusion in apps of material covered by any “Excluded License” — a term of art long ago promulgated by Microsoft in its agreements.  This term includes GPLv3 and its variants, but also any other copyleft license.