Twitter is a social media platform that allows users to post and interact through messages called "tweets," which can be up to 280 characters long. It enables people to share thoughts, news, and updates in real time, making it a popular tool for communication and information dissemination. Users can follow others to see their tweets and engage through likes, retweets, and replies. Twitter is used by individuals, organizations, and public figures for various purposes, including social networking, marketing, and public discourse. Its hashtag system helps categorize discussions and trends.