This paper addresses emerging modes of educational governance constituted through new online platforms for teacher professional development. Specifically, I focus here on the OECD's "PISA4U" ('PISA for you'), an online professional learning platform comprising structured assignment modules and peer-to-peer collaborative activities based on PISA insights. I critically explore how the PISA4U platform, as both a data infrastructure and a new organisational form, forges new relations between otherwise unconnected schooling spaces and actors, and creates new markets and users for the OECD's educational testing, data and professional development services. Rather than simply providing an online forum for teacher dialogue, collaboration and learning, I conclude that PISA4U problematically enables the OECD to consolidate their status as the global expert in education by providing a technical and discursive platform from which to speak to the teaching profession, which risks displacing more professionally oriented forms of teacher knowledge and expertise.