The changes to the newsfeed, whose look and feel has remained largely unchanged since its inception, include a division into several sections, with separate areas for photographs and music.

The overhaul, which standardizes the feed across mobile devices and desktop computers, is designed to keep users active and interacting as well as appeal to advertisers, as Facebook battles Google Inc for Internet market share.

CEO Mark Zuckerberg had singled out the feature as in need of a makeover as recently as January, when the company introduced "graph search" to address inadequacies in allowing users to trawl for information across the world's largest social network.

Facebook's newsfeed, an ever-changing stream of photos, videos and comments uploaded from friends, is the first page most users see upon logging in. It is one of three "pillars" of the service, along with search and user profiles.

The last major update to the feature was in September 2011. Since then, the company has incorporated ads directly into the feed and has shifted its focus to creating "mobile-first experiences," because more people now access the social network from smartphones and desktops than from desktop computers.

The addition of advertising, however, prompted complaints from users who preferred an unblemished stream of personally relevant comments, underscoring the difficulty in balancing advertiser-friendly formats - such as larger images - with keeping its 1 billion-plus members engaged.

Facebook shares were up 2.1 percent at $28.04 on Thursday afternoon on the Nasdaq.