This chapter outlines key theoretical and methodological aspects of critical discourse studies (CDS) and suggests how they may be applied to social media data. After a brief overview of the main features of CDS, there is a discussion of what makes data in digitally mediated contexts different and interesting for researchers who adopt a critical perspective to social phenomena. Eight methodological steps from one approach to CDS, the discourse-historical approach (DHA), are presented with specific reference to how they can be applied to social media data. In the final part of the chapter, a case study analysing some aspects of the ‘life of protest movements’ (Arab Spring, Occupy) on the participatory web is used by way of illustration.