Update: Discussion has moved on to a new thread.
After 61 chapters of Harry Potter and the Methods of Rationality and 5 discussion threads with over 500 comments each, HPMOR discussion has graduated from the main page and moved into the Less Wrong discussion section (which seems like a more appropriate location). You can post all of your insights, speculation, and, well, discussion about Eliezer Yudkowsky's Harry Potter fanfic here.
Previous threads are available under the harry_potter tag on the main page (or: one, two, three, four, five); this and future threads will be found under the discussion section tag (since there is a separate tag system for the discussion section). See also the author page for (almost) all things HPMOR, and AdeleneDawner's Author's Notes archive for one thing that the author page is missing.
As a reminder, it's useful to indicate at the start of your comment which chapter you are commenting on. Time passes but your comment stays the same.
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Eliezer Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).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.
The LotR fanfic has a same basic theme as the MoR: Rationality leads to power and corruption. Both have an evil villain who is smarter, more rational, and more conventionally evil than the protagonists. LotR makes it more explicit: The ring makes you more rational, and this is synonymous with making you more evil.
But "corruption" is a word wielded by the less-smart. MoR portrays Voldemort with much more sympathy than any conventional fantasy would.
And we must remember that Eliezer's CEV depends on the supposition that there is no absolute morality, no basis for calling Dumbledore morally superior to Voldemort, or Gandalf morally superior to Sauron. (If there were, then instead of CEV, we would seek to discover a superior morality, or at least to distinguish good morals from bad ones.)
This fits a pattern in which rationality opens ones eyes to possibilities that are shut out by conventional morality; and acknowledging those possibilities makes one appear evil to the conventional eyes telling the story.
I wonder where Eliezer can go with any conventional fantasy story, as their entire purpose is to validate moral presuppositions that (I think) he rejects entirely. Will MoR lead to a vindication of Voldemort?
I expect the story will make explicit what's been hinted at so far: that Voldemort is the product of Dementation, and is brain damaged. This would, by Eliezer's lights, place him in a different moral frame of reference to normal, neurologically intact humanity. Voldemort's not mistaken about how he should be using his talents. He's now an inhuman mind pursuing inhuman ends.