Microsoft Application Virtualization

Microsoft Application Virtualization (also known as App-V;[1] formerly Microsoft SoftGrid)
1-allows applications to be deployed in real-time to any client from a virtual application server. It removes the need for local installation of the applications.
2-Instead, only the SoftGrid runtime needs to be installed on the client machines. All application data is permanently stored on the virtual application server

Resource:
1-Tech Net Full documnet :http://www.microsoft.com/systemcenter/appv/default.mspx
2-Weikipedia:
http://en.wikipedia.org/wiki/Microsoft_Application_Virtualization