A controversial Facebook advertising program introduced in 2007, which posted updates on members' profiles when they interacted with partner websites, such as Blockbuster, Overstock, Hotwire and Travelocity. In 2008, class action suits were brought against certain partner sites as well as Facebook. Although Beacon was changed to opt-in instead of being automatic, the service was shut down in 2009. See Facebook.
The two most interesting developments, in my opinion, are the imminent rollout of Facebook beacons and the integration of mobile payments into Facebook Messenger, the platform is no stand-alone social messaging application.