Social media platforms have been used by firms for a variety of purposes - for building firms’ brand image, increasing customer engagement, providing customer service, among others. However, there is very little research on content strategies adopted by traditional rival firms competing on online social media platforms. This paper seeks to fill this gap by examining whether retailers, traditionally identified as close competitors, mirror this rivalry in their social media content strategies on Twitter. To this end, this study introduces a new metric for assessing competition on online social media, based on content similarity. The authors find that retailers competing closely in traditional context show greater divergence in their content strategies on social media, and firms whose social media content strategies are less similar to content strategies of their close traditional rivals benefit from higher engagement and acquire new followers faster. In examining the mechanism of the effect, the authors find that these divergent firms’ improved performance is attributable to their superior ability to leverage the higher-level affordances of Twitter as compared to their rivals. The results of this study offer valuable insights for firms seeking to distinguish their social media content from that of their competitors.