This qualitative study examines the cultural and social meanings that social media users ascribe to deviations from the norms of the standard Russian language. It uses critical discourse analysis to explore trends and widely reproduced online ‘commonplaces’ in Russian-language internet users’ expressions of their attitude toward breaches of linguistic norms. It focuses on users’ arguments about whether and to what degree linguistic errors are tolerable and on how they justify their criticisms. It also discusses how Runet users assess others’ language as correct or incorrect, and how these assessments have changed over time, finding that since the mid-2010s there has been a hardening of attitudes toward linguistic deviancy, which may be explained by the increase in user numbers and consequent mainstreaming of the Internet in Russia.