Humans naturally communicate by expressing feelings, opinions and preferences about the environment that surrounds them. Moreover, the emotional load of a message, written or verbal, is extremely important when it comes to understanding its true meaning. Therefore, opinion and sentiment comprehension are a key aspect of human interaction. For many years, emotions have been studied individually and also collectively, in order to understand human behavior. The collective or social analysis of opinions and sentiment responds to the need to measure the impact or polarization that a certain event or entity has on a group of individuals. Social sentiment has been studied in politics to understand and forecast election outcomes, and also in marketing, to predict the success of a certain product and to recommend others.