On the other site of mine, I interview Eric Spitznagel, contributing editor of the Believer, veteran sketch comedy writer and author of an upcoming book on what it's like to write porn scripts:

I run another blog that gives advice to writers. How would advice an aspiring porn screenwriter to break into the business?
I wouldn't. I'd tell them to stay away and find something else to do with their time. Because writing porn is just going to end up breaking your heart. You get into it thinking, "I'll just do a few of these things and make some money and that will be the end of it." But it never happens that way. That may be what draws you to it, but if you have any sense of pride about your writing, you eventually lose all perspective. You start thinking that you can write the Great American Porno. After only my second script, I decided that I was going to write something so funny and original and campy that no amount of bad acting or poor production values could ruin it. I imagined that my films would attract a cult following. Fans would show up at midnight screenings dressed as their favorite character and howl over the best lines. It would evolve into an international craze, and soon even critics would admit that my pornos were a fairly decent guilty pleasure. It was the difference between being Ed Wood and John Waters. If porn was destined to be a joke, I wanted to be in on the joke. But it can't happen. It doesn't happen. You eventually realize that porn is stuck in its little cultural niche, and you're not going to be the one to drag it out of the shadows. So yeah, my advice is don't bother.

More here.