▻http://kieranhealy.org/blog/archives/2013/06/09/using-metadata-to-find-paul-revere
Very good article showing the power of (meta)data analysis, using the data about the American rebels collected by the british government. Most users are (wrongly) unafraid of Google or Facebook spying on them because they believe they are hidden like a needle in a haystack. This paper will show them that modern techniques allow to find the needle, using only metadata, not the actual contents of the communication.