Doctor Who: I Think I Know the Doctor's Name (And A Bad Thing About The 50th Anniversary)
Be advised, this article was written with tongue very much in cheek.
Of course the big revelation from "The Name of the Doctor" was not the birth name of the Time Lord, or even that his name was really all that big a secret. No, the real mystery was that somewhere along The Doctor's timeline is an incarnation that renounced that name and committed horrible atrocities. Despite the caption, "Introducing John Hurt as the Doctor" at the end, it's unknown what he will really be called.
The current theory is that between the Eighth Doctor and the Ninth was the Hurt Doctor, and it was he that waged the Time War that destroyed the Time Lords and the Daleks. That's just conjecture, though. I've also seen theories that the Hurt Doctor actually predates the First Doctor, or that he is the modern series interpretation of The Valeyard (An evil possible future Doctor portrayed by Michael Jayston that attempted to execute the Sixth Doctor), or even that he is a mysterious character from the novel Lungbarrow called The Other who helped found Time Lord society in the distance past and later hurled himself through time to be reborn as The Doctor.
The point is that the name of The Doctor has no real power at all. The danger was that his name opened the door to his body in his tomb in the Tardis, possibly leading to the eradication of all his heroics and the revelation of the terrible Hurt Doctor. Which is sad, because I woke up the other day and realized I knew the Doctor's name... his terribly, terribly boring name.
Remember this bit from "The Doctor Dances?"
Rose: Look at you, beaming away like you're Father Christmas!
The Doctor: Who says I'm not, red-bicycle-when-you-were-twelve?
You could say that that was just Nine's little joke, though jokes like that were not necessarily his style. He preferred to plant little truthful hints rather than make up stuff outright. Also, there's no period between meeting Rose when he would be without her for him to go back in time to check that information without her knowing. So the only way that he would already know is if he was really responsible.
Granted, The Doctor met Santa and Saint Nicholas in several spin-off stories, but that hasn't happened in any of the modern ones. Also, it's been revealed that Santa uses Time Loops to accomplish his deliveries. It's possible that since the destruction of the Time Lords The Doctor has had to take over the duties as time travel has become less manageable and harder, with the death of the original Santa probably occurring as a result.
And who does Amelia Pond pray to fix the crack in her wall? Santa. Who shows up? The Doctor.