On Friday, EFF plans to publish "Who Knows When You Are," an informational guide to protecting your temporal privacy. Although location-based services are becoming commonplace, EFF is concerned about a new, more established threat: that data from most communications services can pinpoint exactly when you are, whenever you are.
"There is a timestamp for pretty much every digital interaction you have, whether it's sending an IM or email or accessing a webpage," said EFF Senior Staff Technologist Peter Eckersley in a charming Australian accent. "When you are is strictly your own business. No one — not physicists, nor philosophers — should be able to stake a claim on when you are when you don't want to be."