jargon.artrocity.com
New Hacker's Dictionary the Jargon File v 4.4.6
[Usenet; orig. fr. the Island MUD via Oxford University] Abbreviation for “predictable”, used to signify or preempt responses that are extremely predictable but have to be filled in for the sake of form (the phrase is bracketed by <pred>...</pred>). X-Pred headers in mail or news serve the same end. Figuring out the connection between the X-Pred tagline and the thread is part of the entertainment. For example, it is said that any thread about taxation must contain a reference to Raquel Welch, if only to stop other people from mentioning her. This is allegedly due to a Monty Python sketch where a character declares that he would tax Raquel Welch, and he has a feeling she would tax him.