If Voldemort's possession ability worked like that, though, why wouldn't he just use Quirrel's body for that? You'd think that he would make sure to use his smartest host for anything requiring puzzle solving or careful manipulation.
Perhaps Voldemort doesn't want Quirrell to know certain going plans? Perhaps Voldemort thinks not involving Quirrell is the most effective method of convincing targets that someone other than Quirrell is doing this? Perhaps Hat-and-Cloak's secrecy is to normal people what Quirrell's brilliance is to Harry (convincing), and Voldemort thinks or know that Quirrell can't pull off being H-&-C properly? Perhaps Quirrell is monitored in some way that he can't safely or nonsuspiciously avoid (I can believe Dumbledore setting up some such thing) and so Voldemor...
(The HPMOR discussion thread after this one is here.)
This is a new thread to discuss Eliezer Yudkowsky's Harry Potter and the Methods of Rationality and anything related to it. There haven't been any chapters recently, but it looks like there are a bunch in the pipeline and the old thread is nearing 700 comments. The latest chapter as of 7th March 2012 is Ch. 77.
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.
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.
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: