So a devious entity can shift mass opinion through selective filtering and promotion of content on a social network.<p>I wonder what the nature of a &quot;Pravda effect&quot; would be where people suspect their information source has been corrupted and made unrepresentative and thus will distrust many traditional mechanisms of authority.<p>Is there an actual assuaging of opinion, a disengagement of the process, an increase in conspiratorial beliefs ... what happens?<p>Propaganda does this through smear campaigns - e.g., painting an academic as being egotistical and seeking money (thus making them corrupted by undisclosed motives).  I see this with regard to climate change, evolution, and formerly tobacco smoke.