Whilst there are plenty of problems with the sources of news, the way that news spreads and peoples own way of re-telling and piecing together the information they get amongst each other and through out society can cause just as much harm or good as the reporting itself. The effects of bad reporting or lack of complete information can create nightmares for individuals, companies and politicians as the effect then becomes magnified by the way that information spreads and people try to make sense of the relevant information, and the effects of wild fire gossip on its own can distort information and peoples own views, especially if the media picks back up on that reaction as part of its reporting. This essentially creates an echo chamber, causing disparity between what should be known as fact and fiction, leaving an impenetrable mess of notes and vibrations leaving it impossible to be left with a clear view of anything.
First, lets point out fundamental things about the very individuals and groups that become part of and help accentuate this mess.
A fundamental point point about people in general, and no, it is not that they're inherently evil...no, it is not that they're idiots. No, it's not that we're all involved in a giant inter-continental game of Chinese Whispers. It's that we as people simply do not always have the time nor inclination to keep as close track of the multitude of subjects and hundreds of different things that happen every day. Everything comes to us through many filters we have consciously or unconsciously built, rather like the automatic sorting of spam in your email inbox, amongst potential tagging features that allow you to mark different pieces of mail not just under different topics, but of importance (with the 2 not being mutually exclusive).
A good talk on a subject very similar and has influenced my thinking on this called Filter Failure not Information Overload, which addressed the point that it may not be information overload that is a problem for us moving into a world where we're even more constantly bombarded with information and such on a daily basis, as humanity has always been facing what always seemed an insurmountable amount of information to absorb, but a fundamental filter failure in how we address and handle the information we both send and receive in the modern age.
Because people do not always have the time nor the interest/inclination, this means they are more likely or will definitely miss various amounts of information depending on how far out the topic is from their "core" interests, their social connections, etc. Subsequently, this means the knowledge they do have is likely to be incomplete. Also here comes the social interaction part - they end up relying on or receiving information through friends or family. Second hand information that will likely be simplified for the sake of conversation and brevity. If this process goes through a chain of several people, whilst quicker and easier to digest for someone less interested (and who probably won't take much note anyway), means a far higher likelihood of the absence of potentially important minor and major details. This leads to certain assumptions or overall views being constructed from incomplete knowledge. This is not absolutely dire in all situations though, as sometimes certain issues or topics are just that simple to grasp. However, in quite a few cases leads to what might be important topics having their debates and idle chit chatter coloured and skewed, purely because the information was not there or available to them to be able to take a solid, grounded stance (no matter which side of the fence they're on).
Are we suddenly heading out into space? Is Scotty going to beam me up just to tell me TL;DR?
No. Sadly for you the reader, I do not have the budget for such extravagant special effectences to put down on paper what would surely be wondrous passages of text that you could only imagine.
Using the word vacuum in this case refers to a vacuum of information. When Ripley opened the airlock doors, air rushed out along with several weeks of rubbish that had built up, rushing to fill that empty void, the vacuum of space at work. Much the same applies here. As already touched upon, given a lack of clear information, assumptions, "educated" guesses and judgements based on common sense will rush to fill the void. Effects will vary, but this causes a minimum of slight confusion or misappropriation, and a maximum of infinite internet memes, massive misunderstanding and undermining of the very topics and discussions themselves, to the point where all sides will be convinced that they are right, but when pressed, will never be able to tell you why or how they truly and rationally came to that conclusion. Their beliefs will simply be repeated as if they are obvious and discussions will either break down or become an endless cycle of arguing. If this were applied to society at large, it may even lead to violence and war.