When after done watching a pornographic video, you close the website and due to your crappy internet/computer you continue to here the audio of a chick getting her brains banged out for several more seconds despite the fact that the webpage is closed. Hence the name "ghost porn".
My girlfriend walked in the room and I tried to close pornhub.com really fast but she heard the ghost porn because I have shitty internet.
porn that is made so long ago, that you know for sure that everyone in it is dead.
We just saw some ghost porn from 1910