I'm having a hard time finding the use of correlation in the paper. The author uses differences in differences analysis which also does not use correlations. Was there a correlation analysis performed that you found?

That's fair. That the treatment was the cause of the effect is an assumption made by differences in differences. Is this because you see it as a lack of evidence that Pornhub was the causative event, or was there another event that took place that you had in mind?