Child protection social work’s current concern remains largely with offline harm and injury and separate from the focus on child protection in relation to risks online and children’s use of computer-mediated communication and the internet. This paper draws on original research reporting children’s methods for assessing who they are talking to online, as part of a wider study designed to develop software tools for improved online child safety. It finds that children use similar methods to detect identity online as they do offline, reinforcing the interconnections between mediated and unmediated communication and an ontology of childhood in a digital world that is neither online nor offline, but both. Drawing on the concept of cyborg youth and understanding contemporary child protection in this context allows a re-visioning of the social work role that demands attention to computer-mediated literacy in the assessment of all vulnerable children and in the support of their parents and carers.