OK, since I'm getting the vibe that a lot of people have not been Goatsed, lemme lay it out for you.
Goatse, a.k.a. hello.jpg, is a picture of a naked man, who is grabbing his buttocks and stretching out his anus incredibly wide. Like so wide, if you wanted to shove a football in there you could.
Don't search for it, it's as nasty as it sounds, and definitely don't post it, because that is a bannable offense on 97% of the Internet.