The idea of quoting without copying was called transclusion by the designers of Ted Nelson's Xanadu operating system. The most innovative commercial feature of the hypertext system was a royalty and copyright scheme for use without copying. Whenever an author wished to quote, he or she would use transclusion to " virtually include" a passage by pointing to the original. (This function operates like the "make alias" command on the macintosh. It is a pointer rather than a copy.) Literal copying would be forbidden in the Xanadu system. A fee could be charged for transclusion, every time an individual work was being read or quoted. 

Currently, Ted Nelson has been lobbying for a system of transclusion that does not depend on the Xanadu software. He calls this system "transcopyright," a contractual agreement to allow republication by means of a pointer to the original document or fragment.