Researchers from Microsoft, Carnegie Mellon, and the University of Pennsylvania analyzed 22,484 pornography sites using a tool called webXray to identify tracking tools feeding data back to third parties.

"Our results indicate tracking is endemic on pornography websites: 93% of pages leak user data to a third-party," the study concludes.

Of the sites scanned in March 2018, the study found Google or its subsidiaries had trackers on 74%, Oracle on 24%, and Facebook on 10%. That translates to roughly 16,638 sites with Google trackers, 5,396 with Oracle, and 2,248 for Facebook.

According to the paper, even enabling "incognito" mode on a browser was no defense, as even though such users' actions aren't stored in their history, the data still trickles out to these third parties.