• Rumpelstiltskin would be the prime example here.  By learning the name, and speaking it to the creature, the miller’s daughter got out of the bargain she had made (to be able to spin straw into gold, she had to give up her firstborn).
• In The Tenth Kingdom, the blind woodsman would only release his prisoner and give the heroes his magic axe if they could guess his name.  (Luckily, he kept it in his hat.)
  
• The undoing of the Horned King in The Book of Three by Lloyd Alexander was the speaking of his name.
• In Aidyn Chronicles for the Nintendo64, the main character Alaron lacks a True Name, which binds his body and soul together.  Without it, he is incomplete.
  

The question is, does any of this apply to the real world?

It was, in fact, in my playing of Aidyn Chronicles that I first became cognizant of this whole business.  In it, there is a discipline of magic called Naming set in contrast to the more familiar Elemental (fire, air, earth, water) magic.  At the time, I thought, “What’s the big deal?  Is having a name and giving a name so important?”  This was 2001.

Flash forward to 2007.  I have a daughter now, and she’s struggling to learn everything in the world.  She will eat up new words and start using them immediately.  She feels every word brings her more power.

Well, knowledge is power, names are knowledge, and therefore names are power.  So I guess it makes a bit of sense.  You can know about something.  But this is not just knowing something, it is naming that something.  If you know enough about a thing, you can name it, categorize it, relegate it.  Give a name to your fear, the saying goes.

I suspect naming can have broader powers too… a way of setting the stage for a debate, for example.  If you coin a product name, a movment, a philosophy, or anything, you may well be determining the ultimate fate of that thing.  At the very least, you’re doing a bit of mind control by making a popular name that everyone speaks.

Wikipedia has a bit more discussion in this vein, under the True Name topic.