This post on WP Tavern just reinforces what we already knew. If you have more interesting articles that take you visitors longer to read, your post will be shown to more people.
Facebook announced yesterday that its news feed algorithm will now favor articles that users spend a long time reading. While likes, clicks, comments, and sharing counts are all valuable metrics, they are not always reliable determinants for what users want to see. Facebook discovered this by gathering feedback via its Feed Quality Program.