This document summarizes research on sentiment polarity analysis of Twitter data from different events. It discusses how Twitter data can be used for opinion mining and sentiment analysis. Several papers that used techniques like naive Bayes classifier, support vector machines, and dual sentiment analysis on Twitter data are summarized. The document also provides an overview of the key steps involved in a Twitter sentiment analysis system, including data collection, preprocessing, feature extraction, training a classification model, and evaluating accuracy. The goal of analyzing sentiments on Twitter is to understand public opinions on different topics and events.