Age-old debates on children’s encounters with media technologies reveal a long, fractured and contentious tradition within communication and media studies. Despite the fact there have been studies of e ects of media use by children since the earliest days of broadcasting, the subject remains under-theorised, poorly represented in the literature and not widely understood in media policy debates. Old debates have intensi ed in relation to the study of children and the internet. Pitted between alarmist accounts of risks, excessive use and harmful e ects on the one hand and the many accounts about „digital natives” and the transformational power of technology is the empirical project – represented by EU Kids Online among others – of building an evidence base for understanding the evolving envi- ronment for youth online engagement. In this paper, I situate that body of work in an ecological context, both in the sense of the Bronfenbrenner’s bio-ecological model that has been so important in the new sociology of childhood, as well as in the more loosely de ned theoretical approach of media ecology. e latter tradi- tion, associated primarily with McLuhan and later Postman, frames the media environment as a complex interplay between technology and society in which modes of communication and mediated interaction fundamentally shape human behaviour and social life. ese strands o er the basis for framing some of the issues of evidence-based policymaking relating to internet governance, regulation and youth protection online.