Fanservice

Fanservice is a term used to refer to gratuitous content, usually of a non-graphic sexual nature, included in a work solely to appeal to the fans without adding to the story. Usually involves shirtless men, women in lingerie or bathing suits, nudity of varying levels of explicitness, cleavage or underpant shots, yaoi or yuri, etc.

Non-sexual fanservice can include things like fancy scenery shots, complicated special effects, particularly vile and/or hated characters getting what they deserve, and gratuitous explosions. Everybody loves explosions.