The WashPo until about two months ago had a column debunking false internet memes. They recently killed the column, and the reason they did so deserves discussion.

Where debunking an Internet fake once involved some research, it’s now often as simple as clicking around for an “about” or “disclaimer” page. And where a willingness to believe hoaxes once seemed to come from a place of honest ignorance or misunderstanding, that’s frequently no longer the case. Headlines like “Casey Anthony found dismembered in truck” go viral via old-fashioned schadenfreude — even hate.

There’s a simple, economic explanation for this shift: If you’re a hoaxer, it’s more profitable. Since early 2014, a series of Internet entrepreneurs have realized that not much drives traffic as effectively as stories that vindicate and/or inflame the biases of their readers. Where many once wrote celebrity death hoaxes or “satires,” they now run entire, successful websites that do nothing but troll convenient minorities or exploit gross stereotypes. Paul Horner, the proprietor of Nbc.com.co and a string of other very profitable fake-news sites, once told me he specifically tries to invent stories that will provoke strong reactions in middle-aged conservatives. They share a lot on Facebook, he explained; they’re the ideal audience.
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Frankly, this column wasn’t designed to address the current environment. This format doesn’t make sense. I’ve spoken to several researchers and academics about this lately, because it’s started to feel a little pointless. Walter Quattrociocchi, the head of the Laboratory of Computational Social Science at IMT Lucca in Italy, has spent several years studying how conspiracy theories and misinformation spread online, and he confirmed some of my fears: Essentially, he explained, institutional distrust is so high right now, and cognitive bias so strong always, that the people who fall for hoax news stories are frequently only interested in consuming information that conforms with their views — even when it’s demonstrably fake.
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To me, at least, that represents a very weird moment in Internet discourse — an issue I also addressed earlier this week. At which point does society become utterly irrational? Is it the point at which we start segmenting off into alternate realities?

Those last two questions are extremely important. The longer and more isolated a person or group is separated from reality, the more irrational that group will become. Especially when the person or group actively searches out lies in order to justify their biases.
You can see this happening any time partisans of the left and right encounter each other, as they mostly talk past each other. Neither group has developed the skills or patience for listening to people that hold different values.

Shortly after WashPo killed What was fake, this study came out.

When a big news story breaks, social networks are often awash with misleading information as people either inadvertently, or deliberately, share the story.
This creates what is known as an 'echo chamber'.
Researchers from Italy and the US found that people have the tendency to look for news that confirms what they already believe.
And this in turn creates a network of like-minded people who will spread these common sources and accept them as truth...
'Massive digital misinformation is becoming pervasive in online social media to the extent that it has been listed by the World Economic Forum (WEF) as one of the main threats to our society,' the paper says.

The danger of mass self-delusion involved when society believes lies is obvious.
It's how we have a nation that tolerates insanity such as a permanent state of aggressive war, the torture of people, and a massive security/surveillance/prison state, just to name a few things.

For instance, conservatives oppose everything to do with Big, Scary Government, except for the police, the military and the prisons. In other words, they oppose government oppression, except when it comes to the instruments of government oppression. Then they support it.
Conservatives seem to fear democracy more than an actual military/police state.

As for liberals, they oppose all things racist, except when it comes to bombing and killing brown-skinned people overseas. A good example of this is the Syrian refugees. Liberals hate racist words and policies against those refugees, but not the dropping of bombs on their homes which is causing them to be refugees.

Meanwhile both sides are silent on a government program that literally assassinated people on a global scale, without due process, and nowhere near battlefields. As if this is a normal and rational state of existence that we should just accept, as opposed to a dystopian nightmare.
Both sides are silent to the fact that we are losing our GWOT, and losing it badly. Which you would think would be a Big Deal.
Both sides also rationalize an obviously corrupt political system, as if we simply have no choice in the matter, and berate those who don't support candidates that they find repulsive.

When someone who's immersed in these echo chambers encounters someone outside of that echo chamber, the two seem to be speaking different languages.
For instance, try to tell a conservative that torture doesn't work, and that the military and intelligence agencies oppose it because it doesn't work. They will have never heard of this, and will assume you are making things up.
Or tell a liberal that the term 'humanitarian war' is an oxymoron. They will talk down to you and tell you that you are naive, and that it's only a coincidence that every nation we save by destroying just keeps getting worse.

You can't arrive at this warped and twisted environment unless you've left the sane world behind.