Modern Democratic theories and implementations rely on the seperation of powers: Executive (government and police), legislative (parlament) and jurisdicative (court) are seperated. But the power to influence the public opinion is not much controlled, because media are so ethereal, it is so hard to weight them: Not easy to find out who really controls a medium and how much potential it has.
Private media companies became very powerful since the invention of the printing press, cinema, radio and TV, they have become a part of the executive and legislative: Just see the huge PR on election campains, the infotainment and hypes about really knitty-bitty in order to detract the public from the apocalyptic problems of mankind, and the "psychological warfare" treating the own public until it accepts foreign interventions.
If rulers deceive the peasants of facts and intentions we can call it a conspirative act. Since media is nearly the only thing we can rely on for making political decisions, it is most dangerous if they enter a state that corrupted that they can hardly leave it once they´re in it.
By the way, the internet is a medium I put high hopes into, else I wouldn´t write this. But the internet is prone to sabotage, because most data flows through a few knots, so if you bomb down, hack or compromise a few of them you can affect 95% of the world´s available data bandwidth, still 80% after a few days of reconfiguration. The state cares for roads to walk, ride and drive on, it should care for the internet, too.