Facebook's whimsical illustration of the plumbing that news feed uses to sort posts.
Facebook is incorporating some changes into its news feed to make the content that it displays to users more personalized and relevant.
The adjustments comprise three new features that will change the way the news feed's sorting algorithms work: "story bumping" and "last actor," which are rolling out now; and "chronological by actor," which is still being developed.
Each feature will work differently, but they share a common goal -- to filter out the noise in people's feeds and make the content that is displayed more personalized and relevant to them. All three were announced Tuesday during a briefing with the media at Facebook's headquarters in Menlo Park, California. The changes to news feed are aimed at organic content like posts from users' friends and Pages that they follow, rather than advertising content.
Story bumping is the biggest change, Facebook engineers said, and is undergoing a partial launch right now to users worldwide.
Story bumping changes the way that new stories are displayed to users when they log into the site. Previously, new stories that Facebook ranked as being relevant to the user would be pushed to the top of their feeds, but with story bumping, some posts that had appeared farther down in people's feeds and were not seen during a previous session might be bumped up to the top of news feed during a subsequent log-in.
Not every old story will be bumped up in this manner, Facebook said, and news feed's sorting algorithms will still use other signals like the user's previous interactions with the person who made the post to determine whether to bump up the story.
Story bumping is not expected to bring any hugely dramatic changes to how content is displayed within the news feed. In internal tests of the feature, Facebook saw just a 5 percent increase in the number of likes, comments and shares from users on posts made by their friends, engineers reported during the event.
The last-actor feature, meanwhile, keeps track of users' 50 most recent interactions with other people on the site. So if a person hits "like" for a story from someone that Facebook normally wouldn't rank highly in the news feed for that user, subsequent posts from that person might be placed higher in the news feed.
In internal tests, this feature saw an even more modest increase in people's interaction with their feed content, Facebook engineers said.
Facebook's news feed presents a constantly updating stream of content from the people and Pages users follow on the site. News feed content can take the form of status updates, photos, videos, links, third-party app activity and likes.
The company has faced questions over the algorithms that it uses to display news feed content from some users' friends but not others. The algorithm uses "several factors" to determine top stories, including the number of comments, who posted the story, and what type of post it is, Facebook's website says.
Since Facebook launched news feed in 2006, the amount and variety of content it has had to sort through has exploded. On average, Facebook's news feed has to sort through 1,500 posts daily to determine which ones to display to users, the company said.
Tuesday's briefing was intended to provide a little more clarity on how news feed's sorting algorithms really work, and also introduce changes to make it better.
Upon news feed's inception, "there was less going on," said Lars Backstrom, an engineering manager at Facebook who handles news feed's ranking algorithms.
"This is a hard problem to solve," he said, speaking of Facebook's efforts to keep users engaged with the site while cutting back on superfluous or irrelevant content.
The still-in-development "chronological by actor" feature shows that the process to improve news feed is difficult. That feature, which was designed to use chronology rather than strictly relevance to sort news feed posts, actually resulted in less engagement on the site in internal tests. Facebook is taking it back to the drawing board.
In sorting news feed content and improving its rankings, Facebook is tasked with a challenge on par with how Google displays search results, the company said.
"Facebook is one of the only places where you have a problem on the same scale that Google is doing for search relevance, but you have to use very different techniques due to the personalized aspect of news feed," Backstrom said.
More changes to news feed are coming in the weeks ahead, Facebook said.
Facebook applied a series of more cosmetic changes to its news feed in March, highlighting photographs and content from publishers while trimming clutter.