It wasn't only a Canadian curse before Vancouver. People simply called it the World Champion's curse since it also happened to Plushenko in 2002 and Lambiel in 2006. I remember many people, who believed in the curse (either sincerely or jokingly), thought Evan would succumb to it as well. Once Scott Hamilton pointed out that the curse didn't affect an American World Champion coming into the Olympics and Evan won Vancouver, then people started to either talk about the American exception or calling it a Canadian Curse.
Actually ´till 2002 it was mentioned as the Canadian curse. Stojko competed as the reigning World champion at the 1998 Olympics. Anyway, it definetely seems to me that the problem has been mainly the Canadian one, LOL, and now it could be described as a global one concerning the World champions (with the exception of Lysacek of course). So, Chan is affected for both the Canadian curse and the general WC one...
I have not watched the competition yet, but about Joubert: Apparently he had downgrades in his jumps and generally his programmes are not on the same difficulty level as those of many other skaters, but he always is overscored in some PCS.