Hashtagging and functional shift: Adaptation and appropriation of the #

•Hashtags have undergone functional shift through adaptation and appropriation.•We show that this extends to hashtags used in the linguistics landscape.•Urban hashtags vary in commodification, professionalization and deictic status.

Hashtags are a widespread feature of online discourse that has proliferated with the growth of social media platforms such as Twitter and Instagram. It has recently been noted that hashtags are also popular as an instrument for creative self-expression and language play. In this function, they are often used to qualify a user's attitude toward the preceding text, providing a meta-commentary on its content. We argue that this functional shift can be aligend with effects of (pragmatic) adaptation and (sociolinguistic) appropriation.In this paper, we explore a form of functional shift that has so far received little attention, namely the use of hashtags outside of social media in contexts of public/urban space. Based on a self-collected dataset of such urban hashtags, qualitative analysis reveals varying degrees of commodification, professionalization and deictic status in their use. We conclude by linking this semiotic practice to other emerging appropriations of hashtagging in non-digital modes, such as spoken discourse and gesturing.