As with the previous button, it gives users the option of blocking content from certain people without offending them, say through de-friending. The latter alternative severs ties with that person on the social network, without notifying them.
"This means you are still friends, but updates from that person won't appear in your News Feed. The goal of this change is to help people curate their newsfeed and see more of the content that they care about," Facebook said in an email.
The world's largest social network is constantly tweaking its newsfeed - the main page users look at on the network - often by reducing clutter, especially from advertising, and bringing to the surface or revealing the posts deemed most relevant to any particular user.
Facebook began rolling out the "Unfollow" button and a related change to its users on Monday. It added a "Following" button next to the usual "Like" button on a page or next to the "Friends" button on a personal timeline, which will also enable users to block posts.