Update, 12/17/13: Yoni Appelbaum, Atlantic contributor and historian extraordinaire, has passed along some of his own fascinating research into the Santa-tracking story. First of all, he wrote in an email,
It turns out that the military, and other government agencies, had been using Santa to sell their missions long before 1954. At the height of the Second World War, Eisenhower’s headquarters put out a release offering 'Christmas guidance' to war correspondents. It confirmed that 'a new North Pole Command has been formed,' that 'Santa Claus is directing operations,' and that 'he has under his command a small army of gnomes.' The censors, though, suppressed the location of Santa’s headquarters, directed that his delivery methods be described only as employing 'secret devices' or 'special scientific techniques,' and proscribed 'any mention of radar or speculation on the purpose of reindeer antennae.'
Which is both weird and delightful (army of gnomes! radar antennae!), and, regardless, suggestive of the fact that CONAD had a vested interest in PR campaigns as well as military ones. It was primed, basically, to take advantage of the good cheer of Christmas for its own ends—among them, promoting its military technology. Which makes sense, and which would help explain why NORAD would have so faithfully continued the tradition year after year.
Yoni has also found, it's worth noting, disparities in the early stories that informed NORAD's, Snopes's, and other current accounts of the intercepted North Pole calls. When Shoup told his story to the LA Times in 1980, he mentioned an unlisted line that a child had accessed. In a later newspaper story, in 1999, Shoup mentioned a much more limited, Red Phone-style line, and multiple children. My retelling originates from the Snopes account of what happened, but I'd love more documentation. If you have access to that, or know anything additional about the original story, drop me an email (mgarber[at]theatlantic.com). And big thanks to Yoni for sharing his research.
Update, 12/23/14: More documentation has been found! Matt Novak, at Gizmodo's Paleofuture blog, has found evidence that the NORAD story, as repeated below and as Snopes has it, is partially true but partially the stuff of myth—and, in both capacities, the stuff of savvy military PR. According to Novak, "Yes, Colonel Shoup got a call at CONAD that turned out to be a wrong number. But it wasn't on Christmas Eve and there was no misprint in the newspaper, even though Snopes claims there was. It was just some kid who happened to get his numbers mixed up. And as for Colonel Shoup's reaction? It was more like the kind of reaction you'd expect from a military officer in charge of ordering a strike that had the potential to end life on Earth as we know it. Which is to say, Shoup was not amused. And he wasn't inundated with calls throughout the night that his men had to take."
More here, and big thanks (again!) to Yoni Appelbaum for pointing out the new information.
It was 1955, and Christmas was approaching, and Sears had a new idea for a yuletide gimmick. In local newspapers, the department store placed ads ... on behalf of Santa himself.
"HEY, KIDDIES!" the ad read, in a greeting that would seem creepy only in retrospect. "Call me on my private phone and I will talk to you personally any time day or night."
The ads then listed local numbers for area children to call to get some one-on-one Kringle time. Which must have seemed, if you were a kid back then, pretty amazing. A direct line to St. Nick! Kids could, finally, bypass the middlemen that stood between them and their gifts—the Post Office, their parents—and go directly to the source. And, even more directly, to that source's enormous bag of loot. You can almost hear the Ralphie Parker voice-over.
Like many innovations, though, Sears's frictionless Santa scheme found itself with an unforeseen problem. In the ad the company had placed in the local paper in Colorado Springs, Colorado, Sears had listed Santa's number as ME 2-6681. Which, according to Snopes, contained a typo: It was one digit off of the intended one. The number Sears had ended up printing and distributing to the city's citizens? The one for, as it happened, the Continental Air Defense Command (CONAD)—the predecessor of NORAD—which, like Santa, specialized in aeronautics. And which, unlike Santa, was based in Colorado Springs.