Keeping a list of names of nodes already in use is important to recognize when references are made to the same node. When creating a link you should recognize that the node you wish to point to already exists or already has a name.
Systems like Hyperties offer to the author a list of dangling links, i.e. links already created but pointing to nodes that do not (yet) exist. For Web-sites there also exist some (freely available) tools to find dangling links (and other information). MOMspider is such a tool, developed at the University of California at Irvine.