Fan service
Fan service (ファンサービス, fan sābisu), fanservice, or service cut (サービスカット, sābisu katto), is material in a work of fiction or in a fictional series which is intentionally added to please the audience. The term originated in anime and manga fandom but has been used in other mediums. It is about "servicing" the fan– giving the fans "exactly what they want." Fan service usually refers to "gratuitous titillation", but can also refer to intertextual references to other series or story and visual elements that audiences tend to desire.
History
Direct and deliberate audience titillation is nearly as old as fiction itself. Examples which can be found in early works include meta-references, where the work or audience is referenced within the work itself, homage or parody where the work references another work familiar to the audience, asides where a character in a work directly speaks to the audience, cameos where characters or persons familiar to the audience outside the work (such as the author, a celebrity, or a character from another story) make an appearance in the work for the audience's sake, and other examples of breaking the fourth wall to directly engage the audience. An ancient example can be found in Aristophane's comedy The Frogs where two characters speak in the underworld:
