Facebook explains how it ranks News Feed
On 6 August 2013 Facebook engineer Lars Backstrom, in the first post of the News Feed FYI series, explained that on each visit to News Feed a user has on average 1,500 potential stories from friends and Pages, and ranking picks an average of 300 of them a day from signals of interaction, reactions and hiding. The same day the company announced that unread stories still gathering reactions could return near the top of the feed.
Why it matters
A platform described the ranking of its feed in its own figures for the first time and said why it does not show a chronology: in its tests, without ranking people read fewer stories and reacted less. It became known that the gap between what a person could be shown and what was shown was about fivefold, and that a model, not the time of posting, sets it.
By the post, people had read on average 57 per cent of the stories in their feeds, and 70 per cent once unread ones were resurfaced; in a test with a small number of users the change brought 5 per cent more likes, comments and shares on organic stories from friends and 8 per cent more on those from Pages. The 1,500 carries a footnote mark whose text shows neither on the live page nor in the archived copy. The record does not claim when the feed moved from chronological to ranked order, nor 15,000 stories for active users: the post has no such figure. A report of the same event independent of the company (CNET, reprinted by Scientific American) gives the same figures, but puts the 1,500 as a median of potential stories a day and ties the test to 80 per cent of Facebook employees; it mentions chronological order only as a dropped test of showing one user's stories in order.