The concept of VDS Virtual Document Structure or compound documents is not limited to any one content management software offering. A virtual document structure is a compound document that isn't an independent object as much as a parent cascading into one or multiple child documents of any possible file type. Though at first glance virtual documents might sound like an odd occurrence limited to a few business sectors, the application of virtual documents is literally all around us.
Single Sign on (SSO)
Have support for multiple SharePoint versions
GUI based document management process
Unbounded level of virtual document complexity is supported