Marijuana-related Tweet (1 of 2) (IMAGE) Washington University School of Medicine Caption Washington University researchers found that during an eight-month period in 2013, a marijuana-related Twitter account sent out more than 2,200 messages to some 1 million followers, 73 percent of whom were 19 years old or younger. Credit Weed Tweets @stillblazingtho Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.