Facebook introduces subscriptions
Privacy concerns return with an option to subscribe to updates from people or public figures, even if you're not friends with them. Twitter-like functionality without the pseudonymity; but with increased control over the amount of updates presented and (fortunately) an option to opt-in to the subscription implementation. An interesting move for Facebook, as it undercuts the social significance of generating circles of friends in favour of becoming a dormant follower. Much like Facebook Groups, this is probably going to be left at the wayside in favour of the grown habitual uses of the social network.