Currently DIA uses internet signals collection, social media analysis and human intelligence to identify foreign messaging and popular messages that are harmful

Currently DIA uses internet signals collection, social media analysis and human intelligence to identify foreign messaging and popular messages that are harmful to national security. They will submit requests to have these taken down (as the State Department did to Youtube to take down Al-Alwaki's videos) - though currently Twitter is not very cooperative. I do not know how Twitter would handle a problem like this itself.