User generated content (UGC), available through social networking sites on the Web, offers a wealth of information about the individuals’ world of living. He or she may write extensively in blogs and discussion forums, posts pictures on the Web, tweet through microblogging applications, or publish video material. The explosion of social networks has caused an explosion of UGC on the Web. What was once a privilege of the rich and famous, showing the pictures of persons and their living environment to the world, has become commonplace for everyone. As such, the Web has become a tremendously rich repository of information for current and future generations. The Web has become a mirror of life that captures in great detail opinions, thoughts, lifestyles, events at moments in time, and places worldwide. In addition, the Web has great economical and societal value. In the domains of advertisements and business intelligence there is a definite interest in processing UGC.

The events, persons, objects, and feelings that users write about or report on through photographs and video is of commercial interest as they provide the intelligence that is necessary for effective advertising and marketing. Increasingly, social, anthropological, and historical research will rely on the mining of UGC, also opening many venues of future research.