Facebook is changing every minute!
When you share something on your Google+ stream, your friends or circles can share them onto their stream which can be viewed by their circles appropriately. It also displays who all have shared it with their creative comments on it.
The same thing is now available on Facebook. Facebook displays the people who have shared your post. You can also view what they commented about the post you shared.
Click on the View (x) share to see who all shared your post.