Sexually explicit written and visual material dates back as far as ancient times and has been known to exist in numerous cultures. The U.S. Supreme Court has set standards of legal obscenity, which are always implemented on a state or local level, but they are extremely difficult to apply on a case by case basis. There are many reasons why people are interested in the use of erotica. Viewing and reading erotica provides a source of knowledge and comparison about sexual anatomy and behavior. Erotic materials are used by some to spark sexual arousal rather quickly or to prolong it, depending on the person's appetite at the time.
Some people use erotic readings, pictures or movies to accompany masturbation.
Like sexual fantasies, erotica triggers the imagination and allows people to deal with forbidden or frightening aspects of sex in the controlled environment of the imagination. Erotica gives people opportunities to rehearse in their thoughts acts that they hope to try or are curious about. Preference for one type of erotica over another is a matter of individual taste. Some people prefer the real-life action of films, whereas others prefer to let their imaginations expand on a drawing or photograph or find that stories or other written accounts of a sexually explicit nature offer greater erotic potential. Whatever the venue, there seems to be little difference in the sexual arousal that they help produce.