The Hedonometer measures the average happiness of Twitter on a daily basis and the shooting in Las Vegas has pushed the index to a new low. The previous low point was after the terror attack in Orlando last July. The two other lowest scores have occurred in the past year and a half: the mass shooting of Dallas police officers and the election of Donald Trump, which is the only non-shooting or non-terror attack to achieve such a low score in the 9-year history of the index.
Source: Kottke.org, Hedonometer.org
Sentiment analysis (sometimes known as opinion mining or emotion AI) refers to the use of natural language processing, text analysis, computational linguistics, and biometrics to systematically identify, extract, quantify, and study affective states and subjective information. Generally speaking, sentiment analysis aims to determine the attitude of a speaker, writer, or other subject with respect to some topic or the overall contextual polarity or emotional reaction to a document, interaction, or event. The attitude may be a judgment or evaluation (see appraisal theory), affective state (that is to say, the emotional state of the author or speaker), or the intended emotional communication (that is to say, the emotional effect intended by the author or interlocutor).