4tune

A common shadownet phenomenon, where blank space in a document (such as betfore the punchline of a joke) is filled in with a randomly selected witty or insightful quote. Many public libraries of such snippets exist, while the more prolific users often maintain their own list.

Also, shadowtalk term for the phrase "This space intentionaly left blank", which seems to occupy the same space in more formal or bureaucratic documents.

Etymology: Possibly from the Analogic 4-tuner a digital music player with a notably good randomised playback feature.