– Preface – SIGIR 2015

In this keynote we give an introduction to wisdom of crowds in the Web, the long tail of web content, and the bias involved in the generation of user generated content (UGC). This bias creates the wisdom of ad hoc crowds or the wisdom of a few. Although it is well known that user activity in most settings follows a power law, that is, few people do a lot, while most do nothing, there are few studies that characterize well this activity. In a recent analysis of social network data we corroborated that a small percentage of the active users (passive users are the majority) represent at least the 50% of the UGC. As a sub-product, we also found a lower bound for the digital desert, the content in the Web that nobody reads. These results implies that most of the wisdom comes from a few users, which is not that surprising, as the Web is a reflection of our own society, where economical or political power also is in the hands of minorities.