The rise of digital media use and the ability to be in almost constant connection to the Internet has raised a number of concerns about how Internet use could impact cognitive abilities. In particular, parents and policy makers are concerned with how being ‘constantly online’ might disrupt social and cognitive development. This review integrates the latest empirical evidence on Internet use with relevant experimental studies to discuss how online behaviors, and the structure of the online environment, might affect the cognitive development of adolescents. Popular concerns are discussed in light of the reviewed evidence, and remaining gaps in knowledge are highlighted.