A teen who was bullied on this app for attempting suicide started a petition to have it removed from the app store. The service allows users to anonymously post messages that anyone nearby could see. The result was so horrifying that the company eventually disabled it from happening at geographic locations where schools exist. There is no way to be sure that this was done effectively or well, and there really is no reason for your child to take the risk of using it. It basically adds a virtual "bathroom wall" to your location so that you can write anonymous things.
See our guide to bullying for more details.
We are compiling a list of the many, many cases of bullying reported related to this app.
See our parent’s guides to apps with: