Here is another suggestion from my wife. Mindmap generates an interactive “mind map” based the content of wikipedia. Enter a search term and that term becomes the starting point for the map. I am guessing what the application does is built the representation based on the embedded links (note correspondence between wikipedia entry and mind map below). I would have to think a bit to determine if I felt a “mindmap” met my definition of concept map. I assume the premise is that a mindmap captures the structure of the author(s). Perhaps it just captures the list of things they could find links to.
Anyway, it is interesting and worth a look.
From a map node, you can link to the wikipedia entry or expand the map.
It would be interesting if you could direct Mindmap at any mediawiki site, but at present the selection is limited to wikipedia versions.
Hmm – is authored hypermedia a representation of personal mental structure? Sounds like a research topic.