How long before our computer workspaces are all services, sold to us over the internet, persistent across machines? Cloud desktops seem inevitable.
And you know what? We're halfway there already. What's to stop Apple, for instance, from adding a "cloud app runner" interface to the iTunes store? Then all the apps you've bought for your iPhone would be available from anywhere on the internet, as long as you have the right iTunes login. Tell me that small change wouldn't make iTunes a consumer cloud operating system, complete with a whole host of apps ready to go and user accounts wired up already. That's where we are, people. One tiny step away from cloud desktops, linked to app stores, and we already signed up.
Mokalus of Borg
PS - Browser-based operating systems (eg Chromium OS) are another path.
PPS - Because then your extensions, bookmarks and in-browser apps need to sync with a server to make it worthwhile.