In a recent presentation given by Arthur Shelley at the 2008 actKM Conference, he spoke about the use of wikis in an educational environment for not only learning about knowledge management but doing it using KM practices.
At one stage Arthur spoke of visualising wiki information. I have been looking into this for a while and specifically the offerings from ThinkMap and The Brain.
Arthur mentioned on one of his slides the work being done on Thinkbase.
It sits on top of Freebase providing a visual map of the information provided in the right frame, showing the relationships with other information and information which has similar relationships or facets.
I'm looking into ot a bit further and will hopefully remember to let you know how I go.