Update: Discussion has moved on to a new thread.
The load more comments links are getting annoying (at least if you're not logged in), so it's time for a new Harry Potter and the Methods of Rationality discussion thread. We're also approaching the traditional 500-comment mark, but I think that hidden comments provide more appropriate joints to carve these threads at. So as of chapter 67, this is the place to share your thoughts about Eliezer Yudkowsky's Harry Potter fanfic.
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: one, two, three, four, five, six. The fanfiction.net author page is the central author-controlled HPMOR clearinghouse with links to the RSS feed, pdf version, TV Tropes pages, fan art, and more, and AdeleneDawner has kept an archive of Author's Notes.
As a reminder, it's often useful to start your comment by indicating which chapter you are commenting on.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically:
You do not need to rot13 anything about HP:MoR or the original Harry Potter series unless you are posting insider information from Eliezer Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).
If there is evidence for X in MOR and/or canon then it's fine to post about X without rot13, even if you also have heard privately from Eliezer that X is true. But you should not post that "Eliezer said X is true" unless you use rot13.
I have a couple of theories about how Fred & George managed the Rita Skeeter prank. We know from Quirrel's response that Rita Skeeter's article included evidence from a variety of sources, difficult to fake, and certainly costing more than 40 galleons. The obvious implication is that either they got some covert support (Professor Quirrell/Tom Riddle?), or they found a simpler method. I can think of two.
Modify Rita Skeeter's memories. Make her remember viewing all the evidence, when in fact she hadn't seen them. Hiring someone to do that probably wouldn't have been all that difficult.
Impersonate Rita Skeeter with Polyjuice and turn in the completed article to her editor. Maybe some memory modification as well, to make her not deny it.
This passage does perhaps contain a subtle indication that this is the case:
I would expect that if I wrote a newspaper article, even if I didn't memorize the face of the subject of my article, but I would expect that I would have seen it at some point. Rita Skeeter, however, seems completely ignorant of what Quirrell looks like. It is possible, however, that this would be the case if the memory of writing the article had been implanted.
This seems extremely subtle, even by EY's standards, and there are some alternate explanations I'm considering as well. However, I still think that these methods are much more plausible than any theory of Imperiusing centaurs.