I just spoke with the creator of the “visualizations”: a British
freelance journalist named James Ball. The only thing these
“visualizations” are were charts summarizing the material released
by WikiLeaks (for instance, the charts counted the documents which
originated from each country, the number of documents by year, and
the like). These charts contained no classified information
whatsoever, and disclosed nothing about the content of the cables.
It was the completely innocuous work of a freelance journalist to
inform the public about the categories of documents released.
Those charts were then linked to from the WikiLeaks site, but
hosted separately by Tableau.