This thesis investigates how ordinary language users enact language policy and thus negotiate (standard) language ideology in mundane, online interaction. The language policy work is found in metalinguistic discussions on various social media. The discussions have been triggered by deviations from standard written language, mostly on the level of orthography. The discussions mainly target different aspects of standard language ideology. The three studies included in this compilation thesis identify discursive strategies and reveal the contradictory ideologies underpinning the discussions. The discussions are analysed with an interactional and procedural focus, highlighting the unfolding negotiations of standard language ideology. The results show that standard language ideology is prevailing which, in turn, enables certain realisations. When drawing on standard norms, the participants can use strategies that do not include explicit arguments. However, the discussions also include contradictions and strategies that challenge traditional standard beliefs. These results illustrate the mundane, vivid metalinguistic negotiations in which standard language ideology is primarily enforced, but also challenged. The results illuminate how standardisation is not a mythical and imperceptible process, but one of constant and visible iteration, also in very mundane situations. Furthermore, the pervasiveness of standard language ideology could make it harder for those who deviate from it to be listened to or even to participate at all. In this way, everyday metalinguistic discussions are one among many language policy activities that can enforce loyalty to the standard variety and its position as unmarked.