'The smart way to keep people passive and obedient is to strictly limit the spectrum of acceptable opinion, but allow very lively debate within that spectrum.'
In a sense the net, first seen as flattening the classes, have instead empowered the elite to make both Stasi and Bernays look like bungling idiots.
Rather than crude manual policing etc, computers can both monitor all activity online (and offline, thanks to the likes of smartphones) and insert data to affect opinions and future activity.
edit for clarification.