Twitter is a social media platform launched in 2006 that allows users to post and interact with messages called tweets that are limited to 140 characters. It grew rapidly from its start and by 2011 had expanded internationally to 7 countries and languages. Key aspects of Twitter's growth included encouraging user innovations like hashtags and retweets, making the interface more user-friendly, and politicians and media organizations using it for real-time news coverage of events and political campaigns. By 2016 it had over 300 million monthly active users, 70% of which were outside the United States.