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...