Below is a Harry Potter & The Half-Blood Prince Spoiler. A theory of mine.
Just warning you.
In previous Harry Potter books, Dumbledore presses that The Dark Lord, Voldemort, has placed a little bit of himself in Harry, the night Voldemort attempted to kill Harry.
Now, as we have learned in the Half-Blood Prince, Horcrux's are use to devides a person's soul into halves, or as Voldemort wanted, multiple pieces.
What if, what Voldemort really put into Harry, as it IS part of himself, was a piece of his Horcrux?
Perhaps that is why Harry does so posess many of Voldemort's powers. Harry was, after all, "trasnferred" some of the Dark Lord's abilities.
I think I just sort of figured out Harry Potter.
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PLEASE PASS THIS ALONG.. *wibbles*