Over the last few decades we have seen the global rise of new forms of psychological and information warfare. The goals of these operations are essentially the same; to make some part of the population of your adversary believe some information and/or doubt/question other information. Information that they receive through an information channel; to influence that population.
Most people in a majority of nations get their information or news from some form of electronic source or channel. Most of these sources are now connected to the internet or a network in some way. These information channels are vulnerable because of these connections. They may be vulnerable to direct manipulation through hacking and consequent leaking and/or directly changing content. Or they may be vulnerable through more subtle indirect manipulation through the introduction of misinformation.
The later type of manipulation would be like an enemy soldier putting on one of your side's uniforms and sneaking into your trenches to spread false rumors (information). Rumors like "Our unit is almost out of ammunition" or "the enemy is much (larger/smaller) than our command is telling us". Except that the misinformation we are talking about here is going out over social media, on fake news sites, through false videos, and by all manner of combinations of these channels. In this context the enemy soldier may not even be a real person but rather a bot or a bot-network program designed to mimic a human being online submitting comments, posting stories, uploading videos or other content as well as links to all of the same.
In addition, spreading ideologies, conspiracy theories, and propaganda explicitly has never been so proliferate. These may pass explicit or implicit operational directives to followers thus literally acting as part of an adversaries command and control.
The most dangerous aspect of all of this information warfare is in its Psy Ops potential to cause a significant part of the adversaries population to doubt the truth or be unsure of what to believe. Even if they don't get a population to wholeheartedly believe what they are pushing through information warfare tactics, if they cause a population to loose the ability to discern truth among information sources or to not believe in their own media's relative objectivity, or their government's legitimate claims then the enemy has won. Also if an adversaries information warfare tactics cause a population, government and/or media to become continual distracted this may be enough to consider the operations a success.
In other cases a government or established media may enable or amplify the effect of an adversary's information warfare tactics by themselves not being authentic, truthful, and/or transparent. Or by reacting to or concentrating on an adversary's misinformation payload instead of exposing and addressing the tactics, the machinations behind the tactics, the strategy and possible aims of the adversary.
We must be able to tell what information is true. This involves trust. Therefore, governments, credible journalistic media organizations, and social media firms must find ways to establish trust frameworks that allow people to verify the veracity of the information that they communicate without violating free speech, freedom of expression, and freedom of the press.