Imagine a world where there are thousands of companies out there that produce these strange little unpleasant pellets of food that they want people to eat. They don't want people to buy them—the company is happy to send out pellets for free because they make money when the pellets get eaten. (Let's not worry about how that could make economic sense. Maybe the pellets are made of sequestered carbon and the company is selling carbon credits.)

So all these companies want to get millions of people eating their pellets, but people don't want to. They don't taste very good and they've got, like, better shit to do with their lives.

But people do like eating other food. And usually they have to pay for it, which kind of sucks.

An opportunity exists here, and "social eating" companies pop up. These companies will ship you food for free, and you can eat as much as you want. What joy! The only catch is they've mixed some of these not-very-tasty pellets in with the food they send you. The social eating companies get paid by the pellet companies, which is how they're able to make and send you food for free.

Here is the interesting question: What kind of food do the social eating companies make? You might think that since they want to get as many people eating their food mixed-with-pellets as possible, they would make the best food they can. And, indeed, they do want to make food that is scrumptious, compelling, and mouth-watering. But what they don't want it to be is satisfying. Because once you're sated, you stop eating. That's the last thing they want because the more pellets you choke down, the more they get paid.

So what they make is junk food like chips and cookies. Each serving is a single tiny delicious bite, but as soon as it goes down, you're even hungrier than before. Its high in anticipation and desire, but low is satisfaction and satiety. You crave it, but once you have it, you don't actually feel any better. If anything, the craving is even more intense.

Now apply that metaphor to information. The most junk-food-like content is the stuff that triggers anxiety and anticipation if you don't watch it: fear of missing out, question-inducing "You won't believe...", alarming "You're doing ___ wrong...", etc. The content doesn't make you feel good if you do watch it, it makes you feel bad if you don't. Because that way, when you do watch it, the nagging anxiety goes away a bit, but you still don't feel "done" and still want more.

that which inflames or causes controversy gets sent around or reposted.

clicks == money.

as does "sponsored content" aka "post this to everyone who meets demographic groups X and Y". just so happens that some of those people want folks angry about some topic.