@DeathByVisualStudio: It's literally a conditional. IE10 still runs ActiveX on the desktop, so if you want your flash and silverlight goodness you can click the "show this page on the desktop" button in IE metro-mode and you'll be able to see it.

IE10 metro is the same code as IE10-desktop, it's just one of the design decisions was to take all of the crud like flash and silverlight and BHOs and not allow them for Metro.