Online social networking sites such as Facebook and MySpace have become increasingly popular, with close to 500 million users as of August 2008. The introduction of the Facebook Developer Platform and OpenSocial allows third-party developers to launch their own applications for the existing massive user base. The viral growth of these social applications can potentially influence how content is produced and consumed in the future Internet. To gain a better understanding, we conducted a large-scale measurement study of the usage characteristics of online social network based applications. In particular, we developed and launched three Facebook applications, which have achieved a, combined subscription base of over 8 million users. Using the rich dataset gathered through these applications, we analyze the aggregate workload characteristics (including temporal and geographical distributions) as well as the structure of user interactions. We explore the existence of 'communities', with high degree of interaction within a community and limited interaction outside the community. We find that a small fraction of users account for the majority of activity within the context of our Facebook applications and a small number of applications account for the majority of users on Facebook. Furthermore, user response times for Facebook applications are independent of source/destination user locality. We also investigate distinguishing characteristics of social gaming applications. To the best of our knowledge, this is the first study analyzing user activities on online social applications.
