Twitter is a popular social media platform that allows users to post short messages called tweets. It has over 645 million active users worldwide who sign up at a rate of 135,000 per day. Tweets are limited to 140 characters and can be liked, shared, or retweeted by other users. Hashtags are used to categorize tweets by topic and trends show the most popular hashtags. Verified accounts help identify authentic celebrity and business profiles. Information can spread quickly on Twitter through eyewitness reports, though false reports are also possible.