In a number of new studies, including https://doi.org/10.1371/journal.pone.0203958 the ramp up of fake news comes as no surprise. We now understand the ugly side of the Internet and social media environment.
In the article, Echo chambers and viral misinformation: Modeling fake news as complex contagion by Petter Törnberg he poses a theory about networks of people online and the associated opinions that they foster. As with all groups, information is social and the reinforcement of held opinions is a self reinforcing effect of these networks.
I see that most important dialogue about this to be the comments he makes on the changed environment he suggests for how we seek information, how we form our opinions and how we debate.