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Eliezer Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).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 remember the author's comments some time ago to the effect that he was surprised that many readers (myself included) weren't immediately sure that Quirrell is Voldemort. Has anyone considered that this might be a trans-forth-wall version of Bystander Effect?
The (presumably omniscient) narrator isn't pointing out that Quirrell is Voldemort. The (presumably well informed) Professor Dumbledore has disclosed no such suspicions to the reader. (Presumably cunning and logical) Rationalist!Harry hasn't made any connections between the sense of doom, harmonic magic interaction, and the constant encouragement to be evil.
Thus, any doubts the reader has about Quirrell's identity can be easily rationalized away by the apparent lack of concern from the (apparently) intelligent, fictional characters.
The narrator isn't omniscient; he only tells us things from certain characters' points of view. I agree that it is suspcious that neither Dumbledore nor Harry think of this. But in fact neither has any reason to suspect that Voldemort is still alive, while we (having read the original series) do. (Also, Dumbledore was really bad about this sort of thing in canon.)