This paper explores the use of different languages and instances of code-switching as displays of identity construction in 474 status updates (SUs) and 795 responses to status updates (RSUs) in two groups of 10 Facebook users. The UK-based focus group primarily draws on English, while the Swiss-based focus group makes use of a number of different languages and thus displays a more multilingual identity. While in the Swiss focus group status updates are predominantly written in lingua franca English (targeting the wider Facebook group), when engaging in exchanges for a smaller group of addressees interlocutors often draw on the offline established language code. Code-switches often function as sources for the enactment of culturally-specific genres, to index a particular addressee and connected with this one’s alignment towards him/her, for formulaic discourse purposes, and to mark that the SU or RSU is humorous (cf. Androutsopoulos, in press). By serving these functions, the display of multilingualism can be linked to identity construction in the highly performative practice of writing status updates and responses to them.