The Tech Report writes Windows 8 will be capable of storing setting in the cloud via Windows Live. This will be an optional feature.
As Microsoft's Katie Frigon explains on the Building Windows 8 blog, Windows 8 will use Windows Live IDs to store user settings in the cloud, making customizations system-independent. When you log into a Windows 8 machine with your Windows Live ID, you'll purportedly be able to:
Associate the most commonly used Windows settings with your user account. Saved settings are available when you sign in to your account on any Windows 8 PC. Your PC will be set up just the way you are used to!
Easily reacquire your Metro style apps on multiple Windows 8 PCs. The app’s settings and last-used state persist across all your Windows 8 PCs.
Save sign-in credentials for the different apps and websites you use and easily get back into them without having to enter credentials every time.
Automatically sign in to apps and services that use Windows Live ID for authentication.
When you buy a Windows 8 PC and set up your user account for the first time, you can optionally choose to create an account that is associated to a Windows Live ID.