The evolution of porn is pretty fascinating IMO. It's just sex afterall. There's only so much you can do with a vagina, cock, mouth, ass, and tits. So instead, producers get very specific, like just ass. From there, you branch put again. Gaping, large object insertion, enemas, ass to mouth, pushing objects from the ass, prolapse, and even things like farting and scat. The producers of porn have successfully expanded and exploited the product of pornography to such a degree that they can target a very specific subset for each and every sexual act imaginable. Think about it. You could do a search right now for a redheaded, curvy, milf, interracial, ass to mouth threesome with swallowing and you'll get hits. It's amazing really. This isn't even getting into all of the extremely important psychological aspect of porn. Things like domination are broken up into dozens of sub categories like lezdom, femdom, toilet slavery, facesitting, pony play, corporal punishment, subs as furniture, ect. And each one of those is further broken down by location, body type, which perspective the viewer is represented by. Again, it's amazing.
Here's a quick evolution of porn as I have seen it since the 80's:
Anal was rare. Cum always landed somewhere. Ass, tits, butt, belly. Lots of pubic hair.
Then anal became not so rare. Then anal became so insanely popular that you could rent a movie called "100% Blowjobs" and you could count on at least 3 anal scenes in there.
Anal variations start to make their appearence. Gaping is now seen almost everywhere, along with ass to mouth. Somewhere along this time (late 90's), it actually became ok to cum inside a woman's mouth, pussy and ass. (Btw, the story of the accidental discovery of anal gaping is pretty hilarious. It's right up there with the scientist who accidentally discovered vulcanized rubber as far as it's impact on the world around us.)
Pubic hair disappears over night.
Interracial and gangbangs are brought to the forefront.
Bukkake is actually a thing. Aomg this time, region specific porn starts getting popular. JAV, Brazil, Euro, you name it. It is branded and marketed as such.
PoV starts to really take off (late 90's/early 2000's). This same time was a porn renaissance of sorts. Lots of young, male talent enters the industry in directing and producing roles and really start to focus on particular fetishes and bring them to the mainstream.
Once the Internet really gets into full swing, ameateur starts to really take off. Dueling blowjob queens Wifey and Heather Brook show two different pro-am sides of the same coin. (Heather retires very early to focus on raising a family while Wifey is still going strong today and is rich as fucking shit. Both women only performed with their spouse, although Heather had a girlfriend stop in once in awhile. Wifey is still with her husband.)
Fuckmachines became a reality.
BDSM has been taken out of the back room and put in the show room. Virtually every movie has bdsm undertones in some shape or form. Women dominating and humiliating men/women has become a major sub genre.
All the crazy stuff is on the table and working it's way into mainstream: fisting, watersports, lactation, scat, ect. Women use dildos in the shape of fists, squirting (and all that goes with it) are substitutes along with A2M and anal insertions/pushing being a poor man's scat substitutes. This stuff is working it's way into mainstream, like it or not. Girls drinking milk enemas and squirting into each other's mouths and swallowing it is pretty much the same thing as pooping and peeing on each other, just "cleaner".
With modern porn, you are either getting exactley what you expect, due to the name or searched subject matter, or it's a fucking wild card. "Hey look, a greater threesome!"(Defined as 2 women, 1 man. A lesser threesome is 2 men, 1 woman). "Oh look, they both came in her ass." "Now what is she doing?" *farts cum into a glass and then drinks it* "Wtf am I watching?"
Today's porn can really take a turn for the weird in the blink of an eye. It's crazy, but I'll take the variety and insanity of today's porn over 80's any day of the week. There will always be tame stuff out there as well. But then again, what exactly is tame?
In the real world I see this odd homogenization in sexuality. Women fuck like men now. They have fetishes and dirty (really dirty) fantasies that they want to act upon them. Meanwhile, men can and often do play the subordinate. This type of role reversal and swapping of traditional roles certianly existed back in the day, but now people are exposed to this stuff so young and it's such an open subject that it is getting more and more common IMO.
I can talk about this stuff all day, but I gotta run. Enjoy the porn thread while it lasts!