“Yes, he is, at least, entertaining”

This paper investigates facework and identity construction on a pro-community water fluoridation Facebook page, drawing on rapport management (Spencer-Oatey 2000) and Culpeper’s (1996, 2010, 2011) taxonomy of impoliteness in English. In contrast to previous work on conflictual political talk on social media, which focuses largely on right/left or socially conservative/progressive polarised topics, it addresses discourse on a topic where conflict is between factions aligned with or against the scientific establishment. The paper shows members of an activist group engaging in face-aggravating behaviour against an ideologically opposed commenter. Even when they profess to be educating the commenter, the core goals of their behaviour are enhancing their own quality and identity face within the group by antagonising the outsider; participants construct an expert identity through performing superior intelligence and education, expressed through displays of scientific knowledge and creative forms of linguistic impoliteness.