The death of one of the world's greatest pop stars is having a global impact, but social media brings into sharp focus the scale of the world's shock and sadness. Previously, we might have learned of a pop star's passing via TV, or a friend or coworker: now knowledge is immediate, and mourning has become more public than private: a collective expression of loss.
According to the Twitter tracking tool Twist (incidentally, Twitter appears to be straining under the weight of the tributes to the star), 22.61% of Tweets currently contain the phrase "Michael Jackson". "MJ", meanwhile, accounts for 9% of Tweets right now. More than 25% contain the name "Michael". In total, at least 30% of Tweets are remarking upon the star's tragic passing, and that's likely an underestimate.