A handful of words can pack a punch.
This year, messages 140 characters or fewer in length helped bring down elected officials, mobilize protesters, break the news of dictator's death and much, much more.
Twitter's growth has helped amplify its reach and the power of its 140-character posts. The social media service now boasts more than 100 million active users and processes 230 million tweets per day.
We've put together our picks for the 13 most powerful tweets of 2011. Are there others we should add to our list? Let us know by clicking "Add a slide" below.