What makes a tweet worth sharing? We study the content of tweets to uncover linguistic tendencies of shared microblog posts (retweets), by examining surface linguistic features, deeper parse-based features and Twitterspecific conventions in tweet content. We show how these features correlate with a functional classification of tweets, thereby categorizing people’s writing styles based on their different intentions on Twitter. We find that both linguistic features and functional classification contribute to re-tweeting. Our work shows that opinion tweets favor originality and pithiness and that update tweets favor direct statements of a tweeter’s current activity. Judicious use of# hashtags also helps to encourage retweeting.