It's more likely a move to try to keep people within the walled garden of facebook - people can't easily move to competitors (like blogs, other social media), i

It's more likely a move to try to keep people within the walled garden of facebook - people can't easily move to competitors (like blogs, other social media), if those competitors can't share to facebook too automatically to ease the transition. It also means they can more easily charge companies for posting (who are the ones most likely to want to post to several services).