Twitter is a microblogging platform that allows users to post short messages called tweets. It gained popularity as one of the hottest tech companies since Google and Facebook. While half of its initial user base came from the US, Twitter has become influential in sociopolitical events worldwide. It employs an open platform and simple interface, allowing users to easily connect with others and engage through interactions like retweets. Nearly all of Twitter's revenue comes from advertising, including promoting tweets, accounts, and trends. Advertisers typically set daily budgets and pay per click or retweet. The document then provides examples of successful marketing campaigns by companies and organizations that used Twitter promotion.