I've seen him ~5 times, in a variety of venues (~500 capacity theatre, ~25000 capacity auditorium, Six Flags, Navy Pier in Chicago).  In every case, he's put on a great show.  I have yet to come out of his show and say "okay, that's enough".

South Park *caused* Youtube
South Park - well, The Spirit of Christmas, which was effectively SP's pilot - was the Internet's first proper Viral Video. Youtube exists, in large part, to support this kind of thing.