This book is situated in the emerging field of multimodal studies. 1 Focusing on multimodality in online texts, it aims to contribute a multimodal perspective to the study of online discourse, which has hitherto focused mainly on language and writing (Barton and Lee, 2013; Crystal, 2001; Jones, Chik, and Hafner, 2015; Page et al., 2014; Sindoni, 2013; Tannen and Trester, 2013). It also adds a case study of YouTube to this body of work that now includes studies of the discourse of blogs and wikis (Myers, 2010), Twitter (Zappavigna, 2012), Flickr (Barton and Lee, 2012), online consumer reviews (Chik and Vásquez, 2016; Vásquez, 2014; Vásquez and Chik, 2015), online newspapers (Caple and Knox, 2015; Knox, 2007, 2014), and Facebook (Lee, 2011; Rambe, 2012).