The wider field of discourse studies is still only beginning to turn its attention to social media despite a number of notable scholarly works. But as yet there has been little that has dealt specifically with issues of multicultural discourse – how language, identity, cross-cultural social relations and power play out in the rapidly evolving landscape of social media. In this paper, I show why discourse studies must engage with theories and empirical work on social media across academic fields beyond discourse studies and linguistics, at how these can help best frame the kinds of research that needs to be done, how to best formulate some of the basic questions of critical discourse analysis for this new communicative environment. I use this as a platform to point to the areas where multicultural discourse studies can work – where all the ambiguities of former studies of ‘identity’ and ‘culture’ are present, but realised in new ways. Yet these new forms of communication are fused into wider patterns of changing cultural values about forms of social structure, knowledge itself and the kinds of issues that tend to form our individually civic spheres.