An interesting point has come up regarding the limitations on applications accepted to Microsoft's Marketplace for both Windows Phone and Xbox: no open source code may be used in the application.
Jan Wildeboer ran across a forum entry and preceded to search through the Microsoft Application Provider Agreement to see exactly where Microsoft stood on the issue of different licenses within their own Marketplace. The section in question comes from the Microsoft Application Provider Agreement in article 5, point E:
e. The Application must not include software, documentation, or other materials that, in whole or in part, are governed by or subject to an Excluded License, or that would otherwise cause the Application to be subject to the terms of an Excluded License.
While at first this may not seem too odd or even unacceptable, it is the definition of just what an "Excluded License" is that becomes disappointing. Basically an "Excluded License" is any that requires the license to be distributed with the software subject to the license. This means your GPLv3, LGPLv3, Affero GPLv3, as well as any others that force coders to include the license with a distribution of the product.
“Excluded License” means any license requiring, as a condition of use, modification and/or distribution of the software subject to the license, that the software or other software combined and/or distributed with it be (i) disclosed or distributed in source code form; (ii) licensed for the purpose of making derivative works; or (iii) redistributable at no charge. Excluded Licenses include, but are not limited to the GPLv3 Licenses. For the purpose of this definition, “GPLv3 Licenses” means the GNU General Public License version 3, the GNU Affero General Public License version 3, the GNU Lesser General Public License version 3, and any equivalents to the foregoing.
Now this doesn't exactly mean that Microsoft is against all things open source, but more likely that they want to attempt keeping applications cleaner in their Marketplace by not having to display the open source license for just one tiny part used in an application. This is probably done just to streamline the process of installing and quickly using applications without having to deal with all sorts of licenses.
It is a bit disheartening though that Microsoft has chosen to forbid any open source software that uses these licenses as there are plenty of good code samples about that would save developers time by implementing the already-existing technologies. However, there is probably a good reason, even maybe just as simple as stated above to prevent any clutter or extra work in installing and using an application.
Don't forget to check out the thread in the forums to see what people are saying on the issue, too.