More like a demo.

You can see it but you can't use it.

Not at all. Porn is closed source. You can't modify it. And most people don't even provide it for free. You either have to pay for it, pirate it or use the ad supported shareware.

Linus Torvalds himself said: "Software is like sex. It's better when it's free."

if I could download it and contribute to it by modifying it/improving it, then it would be something far greater than porn.

some should make… whatever that is! an orgy?

I don't know. If porn was open source, you'd get access to the script, you would have insight into the the number of cameras they use, how they chose the clothes they used in the movie, how much everyone on the team is contributing to the end product. Every time someoke has a cool idea for improvements and the skills to submit a PR, you'd download the thing again just to find out that the thibg doesn't fit into the thing anymore and everybody would be discussing where the error might be and who's responsible for fixing the thing. I like my porn not to be open source, sounds pretty boring for sex. FOSS is pretty cool, though.