NORAD have to track Father Christmas, because he's in North American airspace. If they didn't keep an eye on everything flying around up there, they would soon be in trouble with President Obama!
However, NORAD have also provided us with a little more information about why they've made this data public. It seems that, in 1955, a Colorado store arranged for Santa to receive telephone calls from local children.
Unfortunately the advertisement had misprinted the number to call! Instead of going directly to Santa, the kids found themselves talking to Colonel Harry Shoup, the commander-in-chief of NORAD.
Unwilling to disappoint the children, Colonel Shoup turned to what he knew. He switched on his computer and used hi-tech equipment to confirm that Santa was indeed on his way. He obviously couldn't take wish lists, but he could tell them a lot of things, including that the US military knew for a fact that Father Christmas was real.
The service might have been born of a mistake, but NORAD realized from the response that children wanted to know this stuff. For decades, their staff volunteered to answer the 'phones, as the number was legitimately circulated this time. Every Christmas Eve, they would be there, telling kids where Santa currently was in the world.
Once the internet was invented, things became much easier. Now he can be tracked in real time and children just have to log on to see the data for themselves!
Season's greetings, one and all.