Thomas M. Lento

Feed me: motivating newcomer contribution in social network sites

Social networking sites (SNS) are only as good as the content their users share. Therefore, designers of SNS seek to improve the overall user experience by encouraging members to contribute more content. However, user motivations for contribution in SNS are not well understood. This is particularly true for newcomers, who may not recognize the value of contribution. Using server log data from approximately 140,000 newcomers in Facebook, we predict long-term sharing based on the experiences the newcomers have in their first two weeks. We test four mechanisms: social learning, singling out, feedback, and distribution. In particular, we find support for social learning: newcomers who see their friends contributing go on to share more content themselves. For newcomers who are initially inclined to contribute, receiving feedback and having a wide audience are also predictors of increased sharing. On the other hand, singling out appears to affect only those newcomers who are not initially inclined to share. The paper concludes with design implications for motivating newcomer sharing in online communities.

Open data challenges at Facebook

At Facebook, our data systems process huge volumes of data, ranging from hundreds of terabytes in memory to hundreds of petabytes on disk. We categorize our systems as “small data” or “big data” based on the type of queries they run. Small data refers to OLTP-like queries that process and retrieve a small amount of data, for example, the 1000s of objects necessary to render Facebooks personalized News Feed for each person. These objects are requested by their ids; indexes limit the amount of data accessed during a single query, regardless of the total volume of data. Big data refers to queries that process large amounts of data, usually for analysis: trouble-shooting, identifying trends, and making decisions. Big data stores are the workhorses for data analysis at Facebook. They grow by millions of events (inserts) per second and process tens of petabytes and hundreds of thousands of queries per day. In this tutorial, we will describe our data systems and the current challenges we face. We will lead a discussion on these challenges, approaches to solve them, and potential pitfalls. We hope to stimulate interest in solving these problems in the research community.