While Lucius Malfoy was clearly a powerful individual in the books, his manipulations were fairly clunky, and nowhere near as subtle as portrayed here.
We assume he's competent because Dumbledore keeps referring to him as competent, but Dumbledore does have a motive to exaggerate his enemy's power. He constantly uses Lucius as an excuse to not do something, and he flat out tells Harry early on that weakening Dumbledore strengthens Malfoy.
But Malfoy is in over his head. Every time we see or hear from him, he's getting something wrong, being ineffectual, or being publicly humiliated. By contrast, he seems pretty darn effective in the books. His scheme in Chamber of Secrets was simple and robust enough to work, and even with Harry repeatedly being in the right place at the right time it still ends with the Weasleys discredited and the Malfoys untouched. (Edit: Sorry, misremembered. He goes after Dumbledore prematurely and loses. Good scheme apart from that, though.)
His main obvious difference from canon is the way he's raised his son.
even with Harry repeatedly being in the right place at the right time it still ends with the Weasleys discredited and the Malfoys untouched.
Malfoy gets kicked off the board of governors I thought?
(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: