Goatse

I thought everyone knew about GOATSE, but I was wrong. […] And knowing about GOATSE appears to be one of its secret membership codes, which is what Anil was demonstrating when he cheekily wore the word on his T-shirt […]

Sometimes communities are founded specifically around the images — Facebook has a Goatse appreciation group at the time of writing […]

So they resorted to close-ups of LulzSec's Twitter feed. Specifically, 47 seconds in, the message: "For anyone that doesn't know what goatse is, check it out here, it's really eye-opening:"

For many, the experience of Internet shock sites began with goatse, a notoriously repulsive image that is considered the king of shock sites.

I love goatseing people... :)