Someone, lets say Tracie, searches for a phrase or word on google images. lets say French Fries is searched for, because that's the way Tracie rolls. after a page or two of searching she finds this awesome image:
So she posts it, (after making sure its appropriate, of course.) and then someone else, lets say Shnookems, comes along and thinks of a related search. this one could be but is not limited to: cannibalism.
The chain continues forever. I will start.