To define trustworthiness, the company was testing how people responded to surveys about their impressions of different publishers. To define news, the engineers pulled a classification system left over from a previous project — one that pegged the category as stories involving “politics, crime, or tragedy.”

That particular choice, which meant the algorithm would be less kind to all kinds of other news — from health and science to technology and sports — wasn’t something Facebook execs discussed with media leaders in Davos. And though it went through reviews with senior managers, not everyone at the company knew about it either. When one Facebook executive learned about it recently in a briefing with a lower- level engineer, they say they “nearly fell on the fucking floor.”

Wired