Communication accommodation theory predicts that social power plays an important role in influencing communicative behaviors. Previous research suggests these effects extend to linguistic style, thought to be a non-conscious aspect of communication. Here, we explore if these effects hold when individuals converse using a medium limited in personal cues, computer-mediated-communication (CMC). We manipulated social power in instant messaging conversations and measured subsequent interpersonal impressions. Low power induced greater likelihood of linguistic style accommodation, across between- (Study 1) and within-subjects (Study 2) experiments. Accommodation by those in a low power role had no impact on impressions formed by their partner. In contrast, linguistic style accommodation by individuals in a high-power role was associated with negative interpersonal impressions formed by their lower power partner. The results show robust effects of power in shaping language use across CMC. Further, the interpersonal effects of linguistic accommodation depend upon the conversational norms of the social context.