see also http://getoutfoxed.com/visualization

an open source will be released soon.

Based on Radial Visual Browser:
A semantic data visualization that shows the relationships within complex concept network structures. in this example, the diagram represents the connotations (e.g 'has a border to', 'is part of', 'is spoken in') between countries, languages, continents & oceans based on CIA factbook data. the center node can be clicked for detailed information, while adjacent nodes can be selected to put them in the center. Another variant of this visual browser is capable of visualizing social networks in outfoxed, a firefox extension for social browsing.
by Moritz Stefaner.

If you see any deficiences in links or information, please let us know in a comment.