THAT would be interesting, as a Web OS perhaps?
http://blogs.msdn.com/bowerm/archive/2007/03/23/sharepoint-the-operating-system.aspx
http://blogs.zdnet.com/microsoft/?p=327
SharePoint- Is Just Like Office at Alpesh Nakars’ Blogosphere
http://news.softpedia.com/news/The-Next-Microsoft-Operating-System-is-Not-Windows-It-039-s-SharePoint-49474.shtml