That is most likely the funders goal of the original research.

And when you use "Flickr, FourSquare, Frienster, Last.FM, Digg (from Dec 2010), Yelp, YouTube and so on," you participate in the research.

I was going to be more cynical, and say one could use it to determine ringleaders in a network of adversaries.

I was too skeptical. Any technology can be dangerous in the wrong hands.