The release of Facebook's content moderation guidelines has drawn attention to the difficult work of those whose job it is to review the material.

The company says psychological help is available to all its moderators 24 hours a day.

Angus Crawford spoke to one woman about the impact of a job where you look at some of the worst material the web has to offer.

"It's mostly pornography," says Sarah Katz - Read more about a Facebook moderator's experience