Docked to the right hand side of the screen, it displays real-time updates from your friends, such as wall posts, comments and check-in information, allowing users to see how their friends are interacting with one another -- all from the main screen.
However, users have taken to Twitter to blow the whistle on a major bug with the feature -- not fully rolled out to the 700 million users, involving friends' permissions.
"We are currently testing a feature within the news feed that gives people the ability to see what their friends are commenting on and liking, as these actions are being taken on Facebook.
This test includes a small percentage of Facebook users, just a fraction of a percent. In the coming weeks, as we learn more from this test, we’ll keep making improvements and may expand it to more people."
While this is not yet a fully rolled-out feature -- only featuring on a select number of profiles -- this permissions error is indicative of a permissions error which could fall deeper into the site.
Facebook was immediately unavailable for comment.
Update (00:11 GMT): Spokesperson Jaime Schopflin told me that Facebook refutes this 'bug', and that "this is how photos work".
"When a person tags their friend in a photo, the photo is posted to their friend's Wall where their friends can see it."