Twitter is a microblogging site with over 360 million users globally where people share updates in 140 characters or less. It can be used for personal interests, business networking, and staying up to date on news and world events. Setting up a profile involves choosing a handle, avatar, bio, and deciding who to follow. Proper etiquette includes not overselling, thanking retweets, replying to direct messages, and using polite language. Tools like TweetDeck can help manage multiple accounts and schedule posts.
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