Yay! A question for me!

Well here's the thing about your question--'porn' as we know it is a relatively recent thing, dating from the early 1800's or so, 1857 is when it was really written into law in our modern understanding of it (in england and France, a few years earlier in America). So 'porn' as we know it is only about 150 years old!

This is really surprising to most people, as they tend to think, as you do, of the Karma Sutra and other things as pornography. But they're not, or at least in their original contexts they were not

“the explicit description or exhibition of sexual subjects or activity in literature, painting, films, etc., in a manner intended to stimulate erotic rather than aesthetic feelings” (OED)

I don't know much about the Karma Sutra itself, but I do know that it was a manual for men, describing what they could and couldn't do (with wives and mistresses), and it was seen as an educational, rather than erotic text. It is only when picked up and translated by figures such as Sir Richard Francis Burton (of Arabian Nights fame) that it became 'erotic' because it was contextualized that way, and illustrated that way. Side note: Burton didn't do much of the translation, just took credit for all the work that several Indian translators did. Sidesidenote: Burton belonged to a group of intellectuals called The Cannibal Club, and he once tried to get the group a bunch of human skin in order to make a book. Ick.

Anyhow, you're probably curious how porn became porn then, aren't you? Well, even if you're not, I'm going to tell you, because that's my thesis, and frankly, I don't get enough questions around here!

Allow me to quote here and there from my thesis:

Although pornography is a Greek word literally meaning “writers about prostitutes,” it is only found once in surviving Ancient Greek writing, where Arthenaeus comments on an artist that painted portraits of whores or courtesans. The word seemed to fall more or less out of use for fifteen hundred years until the first modern usage of the word (1857) to describe erotic wall paintings uncovered at Pompeii.

Several ‘secret museums’ were founded to house the discoveries. However, these museums (the first of which was the Borbonico museum in Naples) were only accessible to highly educated upper-class men, who could understand Latin and Greek and pay the admission price.

As literacy rose and the book market developed in England and it began to seem possible that anything might be shown to anyone without control, then the ‘shadowy zone’ of pornography was ‘invented,’ regulating the “consumption of the obscene, so as to exclude the lower classes and women.” (Walter Kendrick, p. 57, The Secret Museum) Critics and moralists responded to the growing market, rising literacy, and the developing public sphere by expressing a deep anxiety over the impact and influences of erotic works. Erotic discourse began to be inextricably linked to a ’type’ of work that supposedly had undesirous effects upon the English public. In Lynn Hunt’s words then, “pornography as a regulatory category was invented in response to the perceived menace of the democraticization of culture.”