Microblogs and social media platforms are now considered among the most popular forms of online communication. Through a platform like Twitter, much information reflecting peoples opinions and attitudes is published and shared among users on a daily basis. This has recently brought great opportunities to companies interested in tracking and monitoring the reputation of their brands and businesses, and to policy makers and politicians to support their assessment of public opinions about their policies or political issues.A wide range of approaches to sentiment analysis on social media, have been recently built. Most of these