Twitter is a social media platform that allows users to post messages of up to 280 characters. It can be used to share one's thoughts, news, videos, and connect with celebrities. Key features of Twitter include followers, tweets, retweets, hashtags, trends, favorites, replies, mentions, and direct messages. Basic terms include followers (fans), tweets (posts), retweets (shares), hashtags (# before a name), trends (popular topics), favorites (likes), replies (comments), and mentions (@username). Increasing followers involves following others, posting fresh content, using hashtags and mentions, retweeting, and following accounts related to one's profession.