Even before Rickroll, I guess, there was a website goatse.cx that showed a gay person who opened his widened asshole wide dragging his butt-cheeks to the sides with his hands. Dropping the link to that picture was a way of trolling people. After that, many creative persons made images referencing to it, and it seems some of them even work in corporations.
2girls1cup was the most unifying phenomenon to ever happen on the internet. It was still the early days of the internet. But it showed how everyone is the same, through peoples reactions, and the actresses. Red or blue, black or white, whatever you think divides you from other humans completely dissolves when she erupts into that cup. In that moment, we are all one.