How does ask.fm work?
Several companies have pulled adverts from the website ask.fm, after the death of a teenager who was bullied online.
The father of 14-year-old Hannah Smith from Leicestershire said she killed herself after being targeted on ask.fm where she faced anonymous taunts and comments urging her to end her life.
The BBC's Clive Myrie explains how the social media website works.
- From the section Technology