Page owners on Facebook have had the option for some time of paying to promote individual posts. The idea being that with some extra cash, you can bypass Facebook’s “EdgeRank” algorithm (which normally only serves your update to a percentage of your followers) and reach more of the fans who have “Liked” your Page.
These promoted posts are actually quite effective; by reaching out to more of your Fan base, you can generally get higher engagement levels.
Recently, Facebook has given Page owners the option to promote the post not only to Fans, but also to their friends – taking your update and getting it outside the network.
I’ve found total reach to be nearly double what it was when promoting the post to Fans. However, engagement hasn’t risen to the same extent.
Overall, I think this is a canny move by Facebook, and it opens up some interesting content possibilities. Clearly, if you have a post that might have a broader appeal, promoting to a wider audience may have benefit. However, if your post is intended to drive particular actions – requiring greater actual engagement – then limiting the promotion to Page Fans (those who have liked your Page) might be the more cost effective option.