Social media platforms are characterized by an immense volume of content that exists concurrently. In this study, we analyze competition and coopetition among social media content. Under a competitive dynamic, the diffusion of one piece of content deters the diffusion of another. Alternatively, a coopetition dynamic means that the spread of a social media post augments the diffusion of another. The purpose of our study is to investigate whether competition or coopetition emerges among social media content and identify determinants of the direction of the interaction. To that end, we formulated a generalized self-exciting point process model and evaluated the model using Twitter data. We generally find that a competitive relationship exists among content, but, interestingly, some content experienced a cooperative interplay. In particular, we observe an asymmetry between large and small content producers in that coopetition favors content published by large producers.