Nielsen's site certainly accomplishes its goal, but what the goal is, in my opinion, is more subtle and complex than simply the conveyance of information.
I would suggest that Nielsen's site, by virtue of the fact it is a site about usability, makes the reader question the decisions of Nielsen's site carefully. In turn, this promotes dialog on what effective design is.
Perhaps this is a bit of a stretch as I am no expert on usability, but I couldn't help noticing my mind wander and wonder at the title of his site, why is the 'use' in red? Why did he choose the "stickies" colors? Why in that order? And so on.
Nielsen readily admits that the usability of his site is bad, but it is distinctive looking.
What these people often fail to realize is that while the website isn't flashy and "nice", it accomplishes its goal, which is to convey information. Nielsen is one of the leading UI experts, and the way I see it you can disagree with him, but you can't just ignore him or write him off, because he can back most, if not every, of his claims with empirical data from the studies he's conducted.