When Windows 8 and Windows RT first launched, Flash in IE 10 would only work on selected sites that were whitelisted by Microsoft. I wrote an article showing you how to make Flash sites work with some manual configuration or with the free Whitelist Flash tool.
Later today, as part of Windows Updates, the IE 10 Flash Whitelist will be a Blacklist, and virtually every Flash site will work automatically (except sites that have known compatibility issues).
According to the MSDN IE Blog:
As we have seen through testing over the past several months, the vast majority of sites with Flash content are now compatible with the Windows experience for touch, performance, and battery life. With this update, the curated Compatibility View (CV) list blocks Flash content in the small number of sites that are still incompatible with the Windows experience for touch or that depend on other plug-ins.
This is definitely welcome news for users of the Surface RT, as IE 10 is the main browser used. And it gets annoying when certain Flash-enabled sites don’t work, even with the work-around.