In the Illuminati trilogy, the word Fnord was a tool used by the Illuminati as a type of subliminal suggestion. The book describes kids in kindergarten being hypnotically conditioned to react with fear and revulsion whenever they saw the word Fnord! anywhere. Then, of course, they were conditioned not to realize they had seen the word at all.

The Illuminati would then seed news articles and advertisements with Fnords whenever they wanted something to be avoided, feared, or simply ignored. Reading a news article describing a politician the Illuminati frowned upon would be lousy with subliminal Fnords, whereas the articles describing the Illuminati lackey would be Fnord-free.

Being able to see the Fnords is said to be one of the first steps in evading the Illuminati's control and becoming enlightened. Sometimes this could lead to even more bizarre occurences, however, such as having sex with giant golden apples, or battling undersea with telepathic dolphins as your allies.