Following last weekend’s deadly riots in its western region of Xinjiang, China’s central government has taken all the usual steps to block citizens from accessing foreign web services: aside from crippling Internet service in general, the authorities have blocked Twitter, removed unapproved references to the violence from search engines and has now apparently moved to bar its citizens from accessing Facebook from most parts of Mainland China just now. Two weeks ago, the government had already blocked just about every Google service, including communication tools like Gmail, Google Apps and Google Talk.