It’s possible to want many things out of porn, many of which are not suitable for discussion here. But I think all readers of Decode would agree that what we most want is that it be educationally accurate. To our defense comes the Blogspot website Blackboards in Porn.

Says the website’s anonymous creator, “I saw a random picture and was very impressed that in an industry that I would imagine operates on the lowest possible overheads, with minimal production values, someone had actually bothered to take the time to write something on the classroom blackboard. And what they had written was mostly correct. It seemed to open up a new world, where the performers and the people filming had other sides to their lives, and could express themselves and show off things they’d learned and thought they’d never need again. It was like they were saying, ‘Yes, I may make my living as a public fornicator, but I still remember Pythagoras’s Theorem.’”

To date, the website has explored the trigonometry of compound angles, the chemical formula of orthosilicic acid, the history of ebonics, and the geography of Imperial Russia. It is also critical of handwriting, something every porn-loving professor should care about.

“The site has suddenly become remarkably popular,” the creator says. “I was getting a few links from people Googling for trigonometry functions, but only a handful each day. The site literally had one page view last Monday and then over 90,000 on Friday. It’s been fascinating to track how the word has spread, a bit like being an epidemiologist. I’ve had an overwhelmingly positive response to the site, and people have been sending in lots of new examples, so I should be able to keep it going for some time.

“Luckily, if there’s one thing it’s easy to find on the internet, it’s porn.”