system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do we associate 'X' letter to erotic/porn related stuff?
gpt
There used to be an actual X rating for films that were considered extremely violent/pornographic/explicit. In the 70s, porn companies started using the X rating for their films. Then as a marketing gimmick they would say their movies were XX or XXX rated (note: neither XX or XXX were ever real ratings applied by the MPAA, they were marketing only), implying that their movies contained even more sexual content than films simply rated X.