Endnotes
Introduction
1It tracks where: David J. Crandall et al. (8 Dec 2010), “Inferring social ties from geographic coincidences,” Proceedings of the National Academy of Sciences of the United States of America 107, http://www.pnas.org/content/107/52/22436.short.
2The accumulated data: German politician Malte Spitz demonstrated the power of geolocation data by making six months of his daily whereabouts available to journalists. Zeit Online (Mar 2011), “Tell-all telephone,” Zeit Online, http://www.zeit.de/datenschutz/malte-spitz-data-retention…