The legend goes that the Sears Roebuck store in Colorado Springs - the location of CONAD headquarters - placed an advertisement in the local newspaper around Christmastime encouraging children to call a given phone number in order to speak directly to Santa Claus. The only problem? The phone number they gave was slightly incorrect, and on Christmas Eve connected an inquiring youngster to an unsuspecting Colonel Harry Shoup, the man in charge at America's top military command centre. Shoup, not wishing to dash said youngster's dreams, humoured the girl and instructed his men to do the same to any other young children who might call in, and thus the Santa Tracker was born, kept alive by NORAD.
The reality is not quite as picturesque, though it's mostly true. The advertisement didn't misprint the phone number, the child merely got mixed up, and it wasn't yet Christmas Eve, rather November 30th, and Colonel Shoup was hardly jolly in his response to the caller, who was in fact the sole caller that night.
The United States military, in fact, had a long prior history of trying to make themselves more palatable to America's youth. During World War II, then-General Eisenhower's office put out an appropriately cryptic release stating that Santa Claus was directing operations at a new secret North Pole command. It was a happy accident that CONAD NORAD were able to establish themselves as the guardians of Christmas, monitoring Santa for any signs of an implied Communist threat.