The wider field of discourse studies is still only beginning to turn its attention to social media, despite a number of notable scholarly works. This paper looks at some of the challenges for a discourse approach to multicultural communication on social media. It sees the global communication landscape as fundamentally transformed and shifted in the ways in which identities and communities play out. The paper concludes by thinking about what the consequence of these are, specifically the way identity is negotiated online, how cross-cultural debate pans out, how the status of knowledge is changing, and the relationship between the online and offline world. The challenge for discourse studies is to create more robust research and studies that provide concrete examples of these changes.