Dave Jolly reports on federal attempts to track the real-world contacts of anyone they consider "a person of interest." Theoretically, this merely means keeping a list of the addresses on the other side of the person's mail:
Real mail is still by far the safest way to exchange money or confidential information. Realistically, the federal government has always known how negligent most of us are about writing those harmless chatty letters that brighten the days of disabled friends and elderly relatives. (Yes, that's a hint. Please print out a few nice little notes about the weather, everybody's health, and the latest cute thing your dog did, now.) And it's never been a secret from Uncle Sam if anybody out there is exchanging mail with convicted felons or foreign terrorists, either...and it's not at all news that that information has been "of interest" to our government. However, real mail in a post office box is much harder for hackers and other criminals to get than e-mail is.