Depending on who you ask, Windows 8 and Windows RT are either awesome or terrible. We happen to fall in the former group (at least as far as Windows 8 is concerned), but there's one thing that is an annoyance to anyone using either operating system: the Internet Explorer 10 Metro browser comes with limited support for Flash. It will likely stay limited for at least a little while too, as websites need to be added to Microsoft's whitelist before Flash functions properly.
If you don't want to wait for Microsoft to add your favorite sites to its whitelist, then you're in luck. One clever developer over at the XDA Forums has found away around Microsoft's whitelist, and this workaround actually lets you determine what sites on the whitelist for your install of Windows 8 or Windows RT. Even better is the fact that this workaround is pretty easy, so it shouldn't be too long before you're enjoying Flash on all your favorite websites. According to XDA Forum member Martin_S, here's what you need to do to get started:
What you will have to do first is go to Desktop IE10 and click ALT --> Tools --> Compatibility View settings. Now UNCHECK the last checkmark with: "Download updated compatibility list from Microsoft".
One that is finished, navigate to C:\Users\[USER_NAME]\AppData\Local\Microsoft\Internet Explorer\IECompatData\iecompatdata.xml and open the file. Then, you need to look for the Flash section in the code. This is your whitelist, and you can add new sites to it by typing in websitedomain.com with "domain" tags on either end. Do that for all the sites you want to add to the whitelist, and then you're very nearly done.
The last thing you need to do before the sites you listed begin functioning properly is clear your search history. The option to do so is found in the Internet Settings section of Internet Explorer's Settings menu. This method has been proven to work in both Windows 8 and Windows RT, so users of either should have no problems creating their own whitelist for Flash. See? We told you it was easy.