Jekyll's Mirror by William Hussey, published by Oxford University Press in 2015.
"Sam is a tortured soul, but his darkest hour is yet to come, when he's invited to take part in 'Project Hyde'. A new social networking site where users can enjoy total anonymity - it's exhilarating at first, until Sam notices that the other users are becoming obsessed with the program - addicted to the cruelty they are inflicting online. Sam watches with a growing sense of horror as his classmates turn into something unrecognisable"--Back cover. Includes reading group notes
A great pick for readers who love getting lost in a good story.
