Seems hard to believe now, but there was a brief era in the early 1970s when young couples went on first dates to upscale movie theaters which were showing X-rated movies.
http://content.time.com/time/arts/article/0,8599,1043267,00.html It started with DEEP THROAT, a movie whose premise was titillating enough in those early days of the Sexual Revolution and whose title was given more notoriety by being attached to an informer in the Watergate Scandal. DEEP THROAT starred a rather fresh and natural-looking young woman who seemed at least to be enjoying herself and the movie's breezy attitude was far removed from the usual tacky depressing of "Stag Films" of earlier years. She was quite a celebrity, with books like LINDA LOVELACE FOR PRESIDENT being released. Later, Linda revealed that she had been performing under duress including violence. Some noted that all this came out only after she had been born again and married and would want to distance herself from those days. I haven't really investigated the whole business, although my instincts would be inclined to take her word for what happened.
But even bigger in the public eye would be Marilyn Chambers. She was an All-American sort of smiling blonde who had in fact appeared on the box of Ivory Snow, leading to many doubts about the slogan "99 and 44//100 % pure," although she likely would float in your bathtub if you got her in there. Marilyn seemed to be the spearhead of a cultural shift toward seeing sex (in movies at least) as being all natural and fun and not shameful at all. Some critics thought that eventually mainstream films would include an outright sex scene, and in fact nude scenes were almost mandatory for a while in the 1970s (that seems to have declined, come to think of it).
Porn Chic didn't last long, for whatever reason. Soon enough, every city had a theater or two in a rundown section of town that showed X-rated movies but the audiences were again solitary males. Quite a bizarre thought, a theater filled with men sitting as far away from each other as they could manage, coats over their laps. Ask Paul Reubens* what the appeal might be. That vanished soon, as well, as VCRs showed up and sales of X-rated cassettes sold beyond the dreams of avarice. Then came DVDs and then came the Internet and porn flooded into homes like an avalanche of flesh. At this point, I think porn is tied with stupid pictures of cats as the dominant imagery on the Net.
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*I give him credit for self assurance. After his arrest for masturbating in an adult theater, the next time he appeared on TV, he jauntily asked, "Heard any good jokes lately?"