Most adults have never heard of the social media site Ask.fm.
It's huge in Europe, and it has about 65 million users.
But half of them are under 18 - meaning that the site's active user base consists largely of children.
And they're using it to hound each other to death.
So far, nine teenagers connected to Ask.fm have committed suicide after receiving scores of hateful anonymous messages on the site.
Ask.fm is ostensibly a question and answer site.
You sign up, and the system allows you to pose questions that anyone else can answer, or answer questions coming from other users.
It also allows you to post anonymous questions. But the format also lets users engage each other in running battles and arguments, and to gang up on each other.
A user's account can quickly fill up with a stream of anonymous, hurtful messages that may or may not be coming from people you know.
Here's an example:
Part of the site's problem is that it's a social media site with virtually no privacy settings and no real identity controls.
Facebook, by contrast, has made efforts to ensure that a high percentage of its accounts belong to real people - and it deletes the accounts of fake users.
It also has privacy controls. You can lock down your account completely, if need be, shutting out the world.
You can't do any of that on Ask.fm.
The teens who have have killed themselves after being hounded by other users of Ask.fm are:
❏ Rebecca Sedwick, 12, who jumped from the top of a cement factory in Florida earlier this month.
❏ Hannah Smith, 14, of England, who killed herself in early August.
❏ Joshua Unsworth, 15, of Engand, who killed himself in April.
❏ Anthony Stubbs, 16, of England, was found in a wood near his home in January 2013.
❏ Daniel Perry, 17, killed himself in July 2013 after being blackmailed by a person he thought he was having an online relationship with, but was also harassed by Ask.fm users who posted to him messages such as "Kill yourself mate."
❏ Jessica Laney, 16, of Florida, who killed herself on Thanksgiving weekend, 2012.
❏ Ciara Pugsley, 15, of Ireland, committed suicide in a wood near her home in September 2012.
❏ Erin Gallagher, 13, of Ireland actually named Ask.fm in her suicide note in October 2012.
❏ Shannon Gallagher, 15. Erin's sister, killed herself shortly afterward because she could not cope living without her sister.
Smith was even bullied after her death. Members of the notorious 4chan bulletin board /b/ - a site dedicated to bringing out the worst in anonymous users - even wrote insulting remarks on her Facebook memorial page.
Some users make "suicide lists".
They appear to be aimed at girls who have been the victim of online bullying and need to be cheered up, in a sort of online solidarity.
Here's what they look like:
Ask.fm's founder, Mark Terebin, has blamed the media for the suicides, and Ask.fm's own users:
Ask.fm has since beefed up it abuse controls. It will make an abuse reporting button more visible on the site, add a dedicated category for abusive behaviour, and restrict the way anonymous users can use use the site.
The changes will be fully implemented by spring 2014, the company says:
"In the light of recent events highlighting the impact online bullying and harassment can have on young people, we engaged professional advisors to conduct a full and independent audit of our site and its safety features.
"This audit has now been completed. Based on the findings and the recommendations that were made, we can today announce our commitment to making changes to Ask.fm's existing policies in three core areas: reporting and moderation, registration and corporate visibility."
Read the company's full statement here.
HOW TO GET HELP
- Lifeline: 0800 543 354 - Provides 24 hour telephone counselling
- Youthline: 0800 376 633 or free text 234 - Provides 24 hour telephone and text counselling services for young people
- Samaritans: 0800 726 666 - Provides 24 hour telephone counselling.
- Tautoko: 0508 828 865 - provides support, information and resources to people at risk of suicide, and their family, whānau and friends.
- Whatsup: 0800 942 8787 (noon to midnight)
- Kidsline: 0800 543 754 (4pm - 6pm weekdays)
If it is an emergency or you feel you or someone you know is at risk, please call 111
For information about suicide prevention, see http://www.spinz.org.nz