A stock market is an aggregation of buyers and sellers of stocks, which may include publicly or privately traded securities. In the 12th century in France, courtiers de change managed and regulated agricultural community debts on behalf of banks and also traded debts, acting as some of the first brokers. Twitter is a social media platform that allows users to send and read short 140-character messages called tweets. It was founded in 2006 and gained worldwide popularity with over 100 million users tweeting 340 million times per day by 2012.