For a little while now, Facebook has been offering users the ability to pay to promote their own posts. In doing so, stories you post and promote are displayed more prominently in your friends' news feed. Now, Facebook is expanding this feature by offering users the ability to pay to promote their friends' posts. By paying to promote one of your friends' posts, you'll ensure that post will show more prominently in other friends' news feeds.
To demonstrate how the feature could be used, Facebook gave the example of a friend who is renting out her apartment. By telling her friends on Facebook, your friend reaches a limited audience. If you promote that post, it will appear higher in the news feed of the people you and your friend have in common.
Although the number of users who would pay to help their friend rent out her apartment may be limited, the feature could be used in a more practical manner to help nonprofit organizations and charities get the word out about an upcoming event, announcement, or fundraiser. The feature could also be used to help congratulate friends and get the word out about the birth of a child or another major life event.
The cost to promote a post varies and depends on a number of factors including your geographic location and how many people the post would reach. Facebook is currently rolling out the pay to promote a friend's post feature to users. Promoted posts are labeled Sponsored and do not appear in the right column of Facebook.