Is this really an IndexingScheme? It is just a visualization of the place you are already at, rather than a different topology that makes connections to different places elsewhere in the graph.
Sure, why not. Let's not get Aristotelian.
The wiki at http://bobmc.net has a sidebar which encourages the mapping of all wiki pages to a central scheme.
One can still create arbitrary pages but relevance to the sidebar map is preferred. To me, this seems like
an indexing scheme. -- BobMcIsaac