Political correctness, seen as a form of linguistic interventionism, and its derivate, political incorrectness, are frequently invoked to take a stand on language. These two expressions are considered as notions whose use is increasing in the media and whose semantic content remains vague. This study focuses on a corpus of French and German metalanguage polemics on Twitter: these are positions on language taken by a speaker in the name of political (in)correctness that uses metalanguage and/or metalinguistic markers. Political correctness is considered here as a formula in order to show how its use in online exchanges makes it possible to organize the relationships between participants and contributes towards shaping linguistic norms. The analysis distinguishes, in a polemical and argumentative context, between the use of the formula to disqualify the other and as a decommitment marker that uses humor to defuse the aggressive character of utterances.