The new world's most popular app could be used to bully people and other dark behaviour, experts have warned.
Yolo has had a rapid growth usually unseen on mobile app stores, and with limited advertising or explanation of how it works. Over the last week it has rocketed up to be top of the free stores on both iOS and Android across the world, with vast numbers of downloads.
It is intended as a way for users to anonymously ask questions to others on Snapchat. The people receiving them can then post them on their Snapchat Stories, allowing followers to see the responses and helping encourage the spread of the app.
But the NSPCC has warned that any app that allows users to send anonymous messages can easily be used to send abuse or to exploit young people in other ways.
The app was developed using Snap Kit, a piece of software by Snapchat that enables app developers to integrate their own products with the popular social network.
Those who see the request can respond via Yolo and if the original poster responds their reply is posted back to their Snapchat Story.
Many other anonymous platforms have been impacted by online abuse in the past.
Andy Burrows, the NSPCC's associate head of child safety online said: "Apps such as Yolo that allow anonymous comments could be easily misused to send abusive or upsetting messages.
"Snapchat should justify how this app meets their duty of care to children.
"It's essential that the Government brings in an independent regulator that will have the powers to make tech companies consider the risks that their services present for children.
"We recently issued a warning on our Net Aware site, which we created with O2, about anonymous apps as they are starting to rise in popularity again amongst children."
Last month, the Government published a white paper on online harms, which proposes the introduction of a mandatory duty of care for technology and social media companies, who must pledge to protect their users or face punishment from a new, independent regulator.
Snapchat has not commented on the app.
Additional reporting by Press Association
