(The HPMOR discussion thread after this one is here.)
The previous thread is over the 500-comment threshold, so let's start a new Harry Potter and the Methods of Rationality discussion thread. This is the place to discuss Eliezer Yudkowsky's Harry Potter fanfic and anything related to it. The latest chapter as of 09/09/2011 is Ch. 77.
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. The fanfiction.net author page is the central location for information about updates and links to HPMOR-related goodies, 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Eliezer Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).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.
If I remember right, a moderately big deal is made of wandless magic in the last couple books of the canon. I don't think it's come up in MoR yet, but it seems simpler to suppose that Dumbledore and canon!Voldemort are performing a wandless version of Snape's Legilimency than to assume a more fundamental difference between the types.
It could just be a power difference. If wandless magic came with no penalties attached, you'd have to be mad to continue to use wands if you can manage wandless magic like Dumbledore can. It strictly dominates wands - you can't be disarmed nearly as easily. (And when we see wizarding children 'naturally' use wandless magic, isn't it weaker than what they can manage with wands?)
A big enough difference of degree can look like a difference of kind.