What draws us to spend an increasing amount of our lives using social media? Do they enable new forms of emotional and affective expression? How do social media attempt to mobilise and manipulate emotion? What are the broader affective implications of living in environments saturated with social media? And how is emotion modelled and conceptualised in the social media context to facilitate research and capitalise it? In this chapter, we explore these questions through focusing on key areas pertaining to social media in relation to emotional and affective life: Motivation and theories of desire, personal information, emoticons and emojis, and sentiment analysis, considered alongside notions of digital and affective capitalism. Understanding emotion related to social media is a nascent, but blooming field of study. Existing research has revolved around a series of concerns, such as the desire to form and maintain relationships, for pleasure, to escape, for information, and to expand the self. The captivating powers of social media have made them of interest to big business, attracting a wide variety of institutions and people who are eager to pioneer ways of generating data related to peoples’ conscious and unconscious emotional lives.