When an image posted by a b3tard doesn't show up in their post (due to e.g, a broken link, or the linked image having been removed from the hosting site). Or the b3tard in question not having read the cocking faq.
Originally derived from the appearance of a little red 'x' where the image should be, although it's something different now. Just to confuse you.
Is b3ta hosting borked? I'm getting a sea of redex.