Storage and data-mining have come a long way in the past 35 years, Felten notes, and metadata is uniquely easy to analyze—unlike the complicated data of a call itself, with variations in language, voice, and conversation style. “This newfound data storage capacity has led to new ways of exploiting the digital record,” writes Felten. “Sophisticated computing tools permit the analysis of large datasets to identify embedded patterns and relationships, including personal details, habits, and behaviors.”

via In ACLU lawsuit, scientist demolishes NSA’s “It’s just metadata” excuse | Ars Technica.

I remember Ed Felton as being one of the leading researchers who uncovered the Sony rootkit fiasco.  Many years ago Sony included a rootkit installer that would install whenever someone played one of their CDs on a Windows PC.  Felton’s blog at the time covered that situation well.