Microsoft's IE Chief: The Browser Is Only As Good As the OS It Runs On
While any site can play Flash content in IE10 for the desktop, only sites that are on the compatibility view list--also known as the CV list--can play Flash content within the immersive experience. We place sites with Flash content on the CV list if doing so delivers the best user experience for those sites. For example, is the content designed to be responsive to touch? Does it work well with the on-screen keyboard or affect battery life? Do visual prompts comply with the user experience guidelines? There is a lot of information on this and guidance for developers that want to submit their sites for the CV list on MSDN.