Up until this school year, MCPS blocked Facebook,

...Maria Salmeron, a junior at Bethesda-Chevy Chase High School just outside Washington, D.C., uses Facebook in student organizing as a leader in the Minority Scholars Program, a youth-led group working to increase the academic success of students of color in Maryland’s Montgomery County Public Schools. Up until this school year, the district blocked Facebook, effectively cutting Salmeron off from a critical mobilization tool. “Facebook is one of the sites that connects you with everyone the most … it’s kept me in contact with people and groups from all over the world,” she said...

 http://www.theatlantic.com/education/archive/2016/04/internet-filtering-hurts-kids/479907/