Is the App Accessible

Writing an accessible app can help you reach more customers.
The platform controls already do a lot of the work needed for your app to be accessible. You should become familiar with the basic accessibility requirements and decide if you want to reach out to this audience. If you do choose to be accessible, follow the accessibility guidelines and ensure you declare your app as accessible during your store submission.
If you are not meeting the accessibility requirements (or have not thoroughly tested for accessibility) don’t declare your app as accessible in the store; that might lead to bad reviews.

Reference (HTML)

http://msdn.microsoft.com/en-us/library/windows/apps/hh700325

Reference (XAML)

http://msdn.microsoft.com/en-us/library/windows/apps/hh700325