YouTube has deleted thousands of videos promoting academic cheating in the last week after a BBC Trending investigation.
The videos all advertised essay-writing services, which can lead to serious penalties for students.
Facebook and Google have been asked by a regulator to stop making money from adverts for these companies.
All the social media companies say they are taking steps to discourage dishonest behaviour.
Seven months after the BBC first exposed YouTube stars selling cheating on their channels, the companies which promise essays written to order are back, and are being promoted across social platforms.
YouTube has removed thousands of videos in the last few days after we sent them more than 850 examples that breached the platform’s rules.
Facebook has also removed advertising for several essay-writing services that the BBC identified this week.