The Internet is an important focus of attention for those concerned with issues of extended cognition. In particular, the application of active externalist theorizing to the Internet gives rise to the notion of Internet-extended cognition: the idea that the Internet can form part of an integrated nexus of material elements that serves as the realization base for human mental states and processes. The current review attempts to survey a range of issues and controversies that arise in respect of the notion (...) of Internet-extended cognition. These include the issue of whether the Internet, as a technological system, is able to support real-world cases of cognitive extension. It also includes issues concerning the cognitive and epistemic impacts of the Internet. Finally, the review highlights a range of issues and concerns that have not been the focus of previous philosophical attention. These include issues of ‘network-extended cognitive bloat’, ‘conjoined minds’, and an entirely new form of cognitive extension that goes under the heading of ‘human-extended machine cognition’. Together, these issues serve to highlight the value and importance of Internet-extended cognition to contemporary philosophical debates about the extended mind. In particular, the notion of Internet-extended cognition has the potential to highlight points of philosophical progress that are not easily revealed by the kind of technologically low-grade cases that tend to animate the majority of philosophical discussions in this area. (shrink)