I think people assume a base level of pop culture :P
Survivor - Hard to not have heard of it in America (if youre not american, this is understandable) since it helped spawn the filth that is reality TV
Dale Earnheart - Also hard to have not heard of him in America (again, if youre not american this is understandable). He is a legend with the rest of his family in racing. I dont watch or pay attention to racing but I have still heard of him. Its like not hearing of wayne gretzky, michael jordan, or tiger woods.
AVGN is slightly understandable, though surprising. He was really popular (as indicated earlier, with nearly a million subscribers which is a chunk more than TB).
Sucks that youtube can just... shut people down. Cant really believe it either, was it because of SF? Does Sega care even LESS about their brandname now?