"Who Controls Your Facebook Feed"

"for all its power, Facebook’s news feed algorithm is surprisingly inelegant, maddeningly mercurial, and stubbornly opaque. It remains as likely as not to serve us posts we find trivial, irritating, misleading, or just plain boring. And Facebook knows it. Over the past several months, the social network has been running a test in which it shows some users the top post in their news feed alongside one other, lower-ranked post, asking them to pick the one they’d prefer to read. The result? The algorithm’s rankings correspond to the user’s preferences “sometimes,” Facebook acknowledges, declining to get more specific. When they don’t match up, the company says, that points to “an area for improvement.”

“Sometimes” isn’t the success rate you might expect for such a vaunted and feared bit of code. The news feed algorithm’s outsize influence has given rise to a strand of criticism that treats it as if it possessed a mind of its own—as if it were some runic form of intelligence, loosed on the world to pursue ends beyond the ken of human understanding...

Facebook’s algorithm, I learned, isn’t flawed because of some glitch in the system. It’s flawed because, unlike the perfectly realized, sentient algorithms of our sci-fi fever dreams, the intelligence behind Facebook’s software is fundamentally human. Humans decide what data goes into it, what it can do with that data, and what they want to come out the other end. When the algorithm errs, humans are to blame. When it evolves, it’s because a bunch of humans read a bunch of spreadsheets, held a bunch of meetings, ran a bunch of tests, and decided to make it better...

But those interactions are only a rough proxy for what Facebook users actually want. What if people “like” posts that they don’t really like, or click on stories that turn out to be unsatisfying? The result could be a news feed that optimizes for virality, rather than quality—one that feeds users a steady diet of candy, leaving them dizzy and a little nauseated, liking things left and right but gradually growing to hate the whole silly game. How do you optimize against that?...

Cox and the other humans behind Facebook’s news feed decided that their ultimate goal would be to show people all the posts that really matter to them and none of the ones that don’t. They knew that might mean sacrificing some short-term engagement—and maybe revenue—in the name of user satisfaction. With Facebook raking in money, and founder and CEO Mark Zuckerberg controlling a majority of the voting shares, the company had the rare luxury to optimize for long-term value. But that still left the question of how exactly to do it...

Mosseri’s instinct was right: The news feed algorithm had blind spots that Facebook’s data scientists couldn’t have identified on their own. It took a different kind of data—qualitative human feedback—to begin to fill them in."
http://www.slate.com/articles/technology/cover_story/2016/01/how_facebook_s_news_feed_algorithm_works.single.html

It's embarrassing how much I care about this.