There's also the question of whether Metro-style IE 10 will support add-ons (also known as extensions) or toolbars. Microsoft wasn't clear on this point. "In Windows 8, IE 10 is available as a Metro style app and as a desktop app," said Steven Sinofksy, president of Windows and Windows Live, on the Building Windows 8 blog. "The desktop app continues to fully support all plug-ins and extensions." Sinofsky didn't explicitly say that extensions won't be supported in the Metro interface, but his comments do suggest that extensions are out for Metro-style IE 10.
Admittedly, a lot of these add-ons wouldn't be missed (especially toolbars packaged with other downloads), and IE was never big on add-ons compared to competing browsers such as Mozilla Firefox or Google Chrome. But some extensions might be missed in the touchable version of IE 10 such as identity managers that help you save passwords and automatically fill out Web forms.
Nevertheless, the lack of plug-ins and possibly extensions should make IE more responsive and faster when using the Metro UI.
This could also be a huge blow to Adobe since the Metro-style interface will be the first thing home users see when they fire up Windows 8 on their laptops and desktops. It's possible that Microsoft could adopt Google's strategy and build Flash right into IE, but that would technically be using a plug-in and thus not be as plug-in free as Microsoft is promising.
Microsoft's comments, while they don't explicitly say this, suggest that Flash will not be included in the Metro-style version of Windows 8. So unless PC users at home reject the Metro-style interface and stick with the traditional desktop in Windows 8 or Windows 7, Microsoft may effectively finish what Apple started and kill Flash on the Web.
Adobe was unavailable for comment at the time of this writing.