I agree that ArtDiaspora.viz is a pretty bad visualization. I think the major problem is one of scalability. It would probably work well for a few artists, paintings, and countries, but for the number of artists in the examples I saw, it becomes impossible to follow any of the connections. There are connections between each section title and every node in that section. This adds a lot of meaningless clutter. It is very difficult to find and artist and trace from the country of origin to the country that the painting was created in. For small numbers of artists, this would probably be okay for determining who painted what, but not for much else.