https://www.recode.net/2017/8/2/16079814/facebook-news-feed-update-mobile-app-load-time-instant-articles

Facebook is once again updating its almighty News Feed algorithm, this time to take into account how quickly (or slowly) a web page loads after a user clicks on a link from their mobile device.

Facebook says it will soon start punishing stories that load slowly by decreasing their reach, and prioritize stories that load quickly for users of Facebook’s mobile app.