Tracking media conglomerates.
http://www.cjr.org/owners/ (Columbia Journal Review)
http://wirerimmed.com/index.php?section=article&id=17 ("The Hierarchies project aims to create a database of corporations, their products and their realtionships to each other.")
See also TheyRule, CorporateWeb, [CorpKnowPedia]
I have always been interested in issues like this one, and expanding it to all corporations. Who owns who, and who owns you, or something like that, wow, TheyRule is great .
What the World Wants and how to pay for it using military expenditure is also pretty cool, check out http://www.osearth.com/resources/wwwproject/index.shtml - JosefDaviesCoates