Please sign and share the petition 'Tighten regulation on taking, making and faking explicit images' at Change.org initiated by Helen Mort to the w:Law Commission (England and Wales) to properly update UK laws against synthetic filth. Only name and email required to support, no nationality requirement. See Current and possible laws and their application @ #SSF! wiki for more info on the struggle for laws to protect humans.
They are the best way to actually visualize the needs and wants of users. They are also fun to write. They have the drawbacks of being (a) fictional (b) focused on extremes (c) not really provably statistically valid. For these reasons we also need statistics to tell us more about the effects we want to have, the victims and users whose choices affect the victims.
See Simple English User Stories for examples of how this technique is being used in other open wikis.