Microsoft changed the default behavior of IE10 on Windows 8 and Windows RT. Instead of Whitelist, they have created Compatibility View list. The Modern IE will allow sites that have Flash, but badly behaved sites will be put into CV issue list and the badly behaved Flash content is disabled. Desktop IE on Windows 8 will enable Flash on all sites, but the Windows RT will enable Flash content on that site, unless it is in CV List. You can read more about it here