Introduction

In a highly connected and globalized world, "institutions other than the nation state are having a profound influence on markets and market behavior" (Kamarulzaman, Veeck, Mumuni, Luqmani, & Quraeshi, 2016, p. 400). In fact, opinions expressed in social networks play a major role in influencing public opinion's behavior in myriad of situations such as political behavior (Larsson & Moe, 2011), financial markets (Bai, 2011; Eirinaki, Pisal, & Singh, 2012), and patients' mood detection (Rodrigues et al., 2016). Social networks can provide extremely valuable knowledge since literally billions of opinions are expressed on such platforms every day. Because of their affective nature, such opinions are generally easy to understand and to act upon (Montoyo, Martiniz-Barco, & Balahur, 2012). In fact, Macnamara and Zerfass (2012, p. 299) argued that companies should systematically conduct sentiment analysis "to identify the issues and topics being discussed, source quoted, and the tone of content—That is, whether it is positive or negative."