Sarah Roberts, a University of California assistant professor who has studied content moderation, has warned that content moderators being exposed to shocking things that appear on the internet could ultimately develop long-term problems.
She told the BBC: "There are no public studies that look at the long-term ramifications of this work.
"We are looking at a huge number of people - and that is growing exponentially - and collectively we should be very concerned about the long-term outcome.
"There is no long-term support plan when these content moderators leave. They are just expected to melt back into the fabric of society."
Roz Bowden previously worked as a content moderator at MySpace.
She explained that at the beginning of her job, she was given very little guidance about how she should approach her work.
She shared: "We had to come up with the rules. Watching porn and asking whether wearing a tiny spaghetti-strap bikini was nudity? Asking how much sex is too much sex for MySpace? Making up the rules as we went along.
"Should we allow someone to cut someone's head off in a video? No, but what if it is a cartoon? Is it OK for Tom and Jerry to do it?"