Fact: The Harry Potter fandom is massively huge.
Fact: There are many brilliant people in the HP fandom.
Fact: Many of these people actually extrapolate from canon when they write fic, RP, or meta.
Fact: There are a finite number of things that can happen in the Potterverse, barring OCs and flying pies.
Fact: This finite number of things grows even smaller when you extrapolate from canon only and don't introduce any new branches of magic or whateverthefuck.
Fact: The goddamned Theory of Natural Selection arose almost simultaneously in two completely different people living in two different countries. They didn't know each other.
Corollary: We're all monkeys with typewriters.
JKR's admitted to reading the editorials on Mugglenet, yes. Yes, there are nods to fandom in this book. You should be squeeing that she cares enough about you, you wankers, not raising your hypocritical fists skyward and demanding high literature. No, her characters are not OOC - wtf wtf - they are her characters. Just because you didn't see a character development coming doesn't mean it hasn't been staring you in the face all along. And even if something seems to be coming out of the left field - wtf wtf - this is her story, her canon, her books. She doesn't owe you anything. Don't like, don't read. Take the damn book back to the store and demand your hard-earned bucks. If you raise a loud enough stink, some local reporter might interview you and you'll be featured in Crackmonkey of the Week.
No, JKR is not reading your fanfic. No, she's not stealing from it. You'd think that based on the first three books alone, back when she didn't have a fandom this huge, you'd get a clue that she's a creative individual who doesn't need to steal other people's ideas to write an amazingly engaging world. She's already proven that. She created this world for you to play in, she doesn't fucking send court orders after you, and you have the audacity to accuse this person of stealing from you? You are making this whole fandom look fucking stupid. Stop. Argh.
Apropos, my post-HBP H/D that's set 10 years after Hogwarts has ballooned to 14000 words overnight. WTF, brain. WTF. It was originally a post-OotP fic set 10 years after Hogwarts, but the new canon, she is my mistress. *answers call*
P.S. There are HBP spoilers in the comments, gang.