The Activity Feed plugin displays the most interesting recent activity taking place on your site. Since the content is hosted by Facebook, the plugin can display personalized content whether or not the user has logged into your site. The activity feed displays stories both when users like content on your site and when users share content from your site back to Facebook. If a user is logged into Facebook, the plugin will be personalized to highlight content from their friends. If the user is logged out, the activity feed will show recommendations from your site, and give the user the option to log in to Facebook.
The plugin is filled with activity from the user’s friends. If there isn’t enough friend activity to fill the plugin, it is backfilled with recommendations. If you set the recommendations param to true, the plugin is split in half, showing friends activity in the top half, and recommendations in the bottom half. If there is not enough friends activity to fill half of the plugin, it will include more recommendations.