EDIT: New discussion thread here.
This is a new thread to discuss Eliezer Yudkowsky's Harry Potter and the Methods of Rationality and anything related to it. With two chapters recently the previous thread has very quickly reached 500 comments. The latest chapter as of 17th March 2012 is Ch. 79.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author's Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
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, seven, eight, nine, ten.
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Eliezer Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).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.
Eh, everyone we have seen be smarter is a wizard, and if the /entire world/ got smarter, that would have derailed history so hard even hogwarts ought to have noticed, so presumably the departure point is something that affected wizardry. The true words of madness being lost? Alternatively, someone coming up with a intelligence boosting potion or spell. Hmm. Lily was working on a way to permanently alter her sister, and she succeeded. If what she came up with was a way to.. I dunno, boost willpower, so that what actually happened is that she stuck with an exercise and diet regime in a way very few people actually do, then I could see the wizarding world dosing everybody and everything with it.. This is moving into wild ass guessing territory.
Well, Petunia was at least able to figure out that Vernon Dursley would be a terrible father.