The aim of this article is to examine how the discourse of formative assessment is perpetuated and transformed in a Facebook group where teachers and other agents meet for discussions and to share advice about teaching methods. Drawing on concepts from critical discourse analysis (Fairclough 1993), the study shows how teachers position themselves as successful and devout practitioners of formative assessment, while perpetuating central concepts such as self-regulation and peer assessment. Additionally, the results show how teachers’ voices intermingle with private actors seeking to align formative ideals with requirements for certain goods and services. In light of these findings, the relation between formative discourse and discourses of marketization and performativity seems dialectic rather than oppositional. It is proposed that the resulting interdiscursive mix pushes teachers towards adopting market-­oriented identities, foregrounding not only the assessable behaviors of students but also those of their teachers.