Facebook Inc (FB) introduced a visually richer, mobile device-oriented "newsfeed" on Thursday, in the most significant changes to date for the social network's most recognizable feature.

The changes to the newsfeed, whose look and feel has remained largely unchanged since its inception, are designed to keep users active and interacting as well as appeal to advertisers, as Facebook battles Google Inc (GOOG) 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.