Anti-extremist crackdown on YouTube, Facebook, Twitter only solves part of the problem. While Twitter, Facebook and Google have been able to curb terrorist content on their sites, it is still readily accessible to those who seek it out. Source 6d.
All those huge social groups that didn't want to block because of 'free speech' what's their excuse now? How it is any different now than it was now? Terrorists will use anywhere and anyone once they are willing to entertain their propaganda.