Former CIA Director David Petraeus' affair was discovered in part because of location data encoded in a series of alleged harassing e-mails that his mistress sent to another woman. The location data in the e-mails helped establish the identity of sender as Paula Broadwell, leading to a warrant to monitor her e-mail, which eventually would lead to her affair with Petraeus being uncovered. "Email, information-wise, says as much about its sender as its receiver. The messages' metadata had told investigators what they needed to know, even if they weren't looking to know it in the first place," this article notes.