'Likes', clicks and page views are some of the most important factors for how Facebook serves up personalised content to its users.

As useful as this is, it doesn’t take into account stories that are important to you but ones that would be inappropriate to like (disasters, deaths). It also doesn’t distinguish between stories you clicked in and out of and ones you spent 10 minutes reading.

The good news is that Facebook has realised “just because someone didn’t like, comment or share a story in their news feed doesn’t mean it wasn’t meaningful to them,” and so time spent on articles will be taken into account. This isn’t so good for creepers and lurkers: the more you linger over your ex’s wedding photos or hate-view a frenemy’s fabulous life updates, the more Newsfeed will serve to remind you that you need to move on.

http://newsroom.fb.com/news/2015/06/news-feed-fyi-taking-into-account-time- spent-on-stories/