This article investigates YouTube metalinguistic comments about language varieties in Ukraine as a "light" practice to demonstrate how knowledge and identities are negotiated online against the backdrop of larger sociopolitical discourses that circulate in and about Ukraine. This work adds to our understanding of online, or "light", identity construction by suggesting that taking up epistemic stances and overtly asserting epistemic statuses are often a part of such identity work. Furthermore, deliberate linguistic choices not only serve to index identities but also create (dis)affiliations and thus can be deployed as a means of inclusion or exclusion from a particular online group, often shifting between (and integrating) local and global themes and audiences. The analysis shows how by drawing on repetition, deixis, pronouns, and lexical choices, YouTube commenters police, reify, and contest the extant language practices and underlying ideologies and in so doing create a foundation for grassroots ideological and political mobilization.