Yep, there are a few Countries where you can´t view it.
@Takumi: Not much Ads here. Sometimes one at the Start, and sometimes one in the Middle. One Episode I watched had no Ad at all. Maybe the Ad System does not work correctly
from wikipedia: In March 2008, Comedy Central made all South Park episodes available for legal streaming on the South Park Studios website, however legal restrictions forbid viewing outside the US.
So did allsp.com and all the other sites. However, beside the adds, the official site seems to offer fast streaming and good quality (and no links which aren't working anymore).