Cross-Drive Analysis is a computer forensic technique that correlates information found on multiple hard drives. The technique, which is still being researched, can be used for identifying social networks and for performing anomaly detection.
Garfinkel, S., "Forensic Feature Extraction and Cross-Drive Analysis," The 6th Annual Digital Forensic Research Workshop Lafayette, Indiana, August 14-16, 2006. http://www.simson.net/clips/academic/2006.DFRWS.pdf
NSF Award 0730389, EXP-SA: Prediction and Detection of Network Membership through Automated Hard Drive Analysis. http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=0730389