So, this is the single change that makes this story an AU?
I was thinking along those lines as well, but at that point in time Voldemort was already significantly different from canon.
It seems like the single change (aside from aspects of how magic works) is that Voldemort is more competent, which forces his enemies to level up and go to more extreme measures. Looking at every prophecy is one of those extreme responses, which then triggered a bunch of other changes relative to canon.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 119.
Plans for next chapter release:
There is 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.)