Definition: Porn, also called pornography or XXX, is the explicit representation of the human body or sexual intercourse in order to produce arousal. It's similar to erotism, which uses images sexually exciting as a form of art, but it's not so explicit.
In past decades, a mass industry for the production and consume of porn has been increasing due to the success of VHS video, DVD, Internet and porn for mobile, as well as a gradual attitude of tolerance about porn.
Generally, erotic contents refers to the representation of arousing materials which are considered art, while porn has usually a lascivious connotation of sexual intercourse, with none or little art value.
The line betwee the erotic world and porn (which, by the way, is usally used as a peyorative term) usually is very subjective. In practice, porn may be considered as extreme erotism, which can be found obscene by some people.
The definition of what is dirty or obscene sex differs between men and women, cultures and time. This leaves legal action of those who are against porn open to great many interpretations. It is also source of jobs and fun for a lot of lawyers from either "side".
