It's a symptom of the way our industry works. Pick a metric and over optimise it. Say you pick the "time to like a post" metric, then as an employee you're inc

It's a symptom of the way our industry works. Pick a metric and over optimise it. Say you pick the "time to like a post" metric, then as an employee you're incentivised to put the most click-baitee article at the top. Now if you pick the "number of ads displayed in feed without drop-out" you may have something similar too. Rince and repeat and you end up with the mess we see. Regarding Instagram, I noticed they started to retain posts from the timeline. So they encourage compulsive checking it the app. Open it once : it shows 2 new posts, close it and open it again, 2 more posts, both old by at least a few hours. They just rewarded your brain for checking the app compulsively. Once I noticed that I couldn't unsee it, and I closed my account.