is a free social networking and microblogging service that enables its users to send and read messages known as tweets. Tweets are posts of up to 140 characters displayed on the author’s profile page and delivered to the author’s followers. Since late 2009, users can follow lists of authors instead of following individual authors. All users can send and receive tweets via website, SMS, or external applications. Twitter was created by Jack Dorsey in 2006. It has gained popularity worldwide, sometimes Twitter described as “SMS of the Internet”. Twitter has been used in a lot of ways such as in campaigning, proceedings, space exploration, educations, and even emergencies. Twitter did a better job of getting information out during emergencies than either the traditional news media or government emergency services. 
