One of the features in the recently announced Chrome OS feature-set is Citrix Receiver. What to Expect in Google Chrome OS. Lifehacker describes it as:
Google's partnered with Citrix to make it easy to deploy desktop applications as a service to Chrome OS. Citrix Receiver is a well-established application that allows businesses to deploy desktop applications, such as Microsoft Excel. Citrix and Google have been working together to make Receiver work seamlessly, making Chrome OS a viable platform for businesses.
Sod businesses, home users would only have to buy one copy of software to run it wherever they are in the house (and whoever) all on cheap, low-powered hardware. I expect to see more of this in other operating systems going forward and even home users moving to a client-server model.