Not to mention the granddaddy of link pranks, Goatse. This excerpt from Wikipedia gives a nice little window info how the web operated back then:

The goatse.cx image has been used by website authors to discourage other sites from hot-linking to them. By replacing the hot-linked image with an embarrassing image when hot-linking has been discovered, an unsubtle message is sent to the offending website’s operators, visible to all who view the web page in question. In 2007, Wired.com hot-linked to another site in an article about the “sexiest geeks of 2007”; the site subsequently swapped the hot-linked image with one from goatse.cx.

Man, I miss the early Internet.