Prompted by the new information we've just been given on JKR's website, I've come up with my very first HP related theory, and I'm very proud of it. :)
JKR has just posted the following on her website (along with many other wonderful new bits of information):
QUOTE
The link I mentioned between books two and six does not, in fact, relate to the 'Half-Blood Prince' (because there is no trace left of the HBP storyline in 'Chamber'.) Rather, it relates to a discovery Harry made in 'Chamber' that foreshadows something that he finds out in 'Prince'.
My theory, then, is that the discovery that JKR is referring to is when Harry finds out that Voldemort "transferred some of his own powers" to Harry the night he gave him the scar.
To quote the scene from CoS:
QUOTE
“Professor,” he started again after a moment. “The Sorting Hat told me I’d - I’d have done well in Slytherin. Everyone thought I was Slytherin’s heir for a while… because I can speak Parseltongue…”
“You can speak Parseltongue, Harry,” said Dumbledore calmly, “because Lord Voldemort - who is the last remaining [descendent] of Salazar Slytherin - can speak Parseltongue. Unless I’m very much mistaken, he transferred some of his own powers to you the night he gave you that scar. Not something he intended to do, I’m sure….”
“Voldemort put a bit of himself in me?” Harry said, thunder-struck.
“It certainly seems so.”
This scene perfectly forshadows any future developments in regard to Harry and Voldemort's connection -- and we can be sure that the connection between Harry and Voldemort will indeed play a very important role in future books.
(This is the first HP theory I've ever come up with, so I'm very proud of it. I'm convinced that is has a very real possibility of being correct. )