Our students use an online library system called Destiny Quest. As well as looking up books and writing reviews, it also includes a messaging feature. The kids can look up other users and send them a friend-request. Once accepted, that are able to communicate with each other - in theory sharing views on books or making recommendations to their friends. Of course, they could message each other about virtually anything.
Our librarian, Miss Mandy, has used this as the perfect opportunity to introduce the children to the importance of being sensible and politer hen communicating with technology. Within this 'safe' online environment, they can practice using social media in a protected space, which is managed and monitored by the library staff. Hopefully, this will lead to a culture of safe and responsible online use as they grow older.