Graph Rank is Facebook’s algorithm which determines what open graph content will be displayed in the users’ News Feed.  Facebook developed this in response to the backlash from users regarding the excessive amount of irrelevant apps appearing in their newsfeed when the open graph system first allowed apps to be launched.  The algorthim seeks to display only relevant apps on the user’s NewsFeed based on the connections the user has made.  For example if a friend likes a certain app then that app is more likely to appear in your Newsfeed.  It also monitors your connections to apps so if you play a word game you are more likely to see similar game apps appearing in your Newsfeed.

Graph Rank works in a similar fashion to Edge Rank, utilizing affinity, time decay and weight.  In the case of Graph Rank, affinity is not only based on interactions but also on common interest.  Weight is based on how often you interact with a person, if you interact on a frequent basis with another user, that will receive more weight than that a user who you have as a friend, but do not interact with.  Therefore you are more likely to see apps displayed in your news feed that your close friends like.

Understanding this system is important to App designers.  They must consider their target audience and try to make the app as relevant and interactive to those users.  Having a high graph rank score will ensure that your app is heavily displayed, and in an organic fashion.