Turns out you can tell who’s important in a group of people by tracking the email traffic within the group. “Researchers have developed a way to use e-mail exchanges to build a map of the structure of an organization. The map shows the teams in which people actually work, as opposed to those they are assigned to. The technique can also reveal who is at the heart of each sub-group. These people often correspond with company-designated leaders such as project managers. But unofficial de facto leaders can also emerge. The approach might even help to pinpoint the heads of criminal or terrorist networks.”