Insanely popular with kids, the question-and-answer service thrives on anonymity, making it fun and dangerous.
David Cameron has called for a boycott on websites that don't tackle bullying, following the death of 14-year-old Hannah Smith.
The young hacker, who's real name is Jake Davis, opens up about his time in the cyberattack collective.
[commentary] Just because a site or app lets you post anonymously doesn't mean it's dangerous. There are lots of good uses for these services.