High-profile UK advertisers including telecom giants Vodafone (a 45 percent stakeholder in Verizon) and BT Group are requesting their ads be removed from the controversial "cyberbullying" Q&A site Ask.fm. The move is in response to growing criticism of the site across the UK media, culminating in the Daily Mail running the front-page headline "Close This Vile Website" yesterday morning. The Mail, which has published 11 articles condemning Ask.fm in the space of three days, claims four UK teens were "trolled to death" by users of the Formspring-style site.

In response to the media frenzy, British Prime Minister David Cameron — who has instigated a crackdown on internet violence and porn — called for a nationwide boycott this morning. Cameron told parents to prevent their children from visiting the site, and called out "the people that operate these websites" to "step up to the plate and show some responsibility." Advertisers that have pulled out in the past 24 hours include Durex, Laura Ashley, EDF Energy, The Sun newspaper, Specsavers, and children's charity Save the Children.

It's not just in the UK that Ask.fm has attracted controversy. As The Verge reported last week, the site was instrumental in the recent spate of cyberbullying at Hudson High School, Ohio. The site currently has over 200 million users, and its founders say it adds as many as 300,000 new users on some days. In response to the recent furore, Ask.fm published an open letter in which the site's founders express their sadness for the recent suicide. In the letter, the founders note:

We would like to reassure all users and parents of users that we are committed to ensuring that our site is a safe environment.

We do not condone bullying of any kind, or any form of unacceptable use of our site.

We have implemented various measures over the past months to continue to improve our users’ safety, and we have implemented improved reporting policies.