Introduction

Seeking information in massive unstructured spaces and delivering it to the right recipients, based on an imprecise or informal definition of their needs, is overall the most pervasively addressed problem in online activity, and a thrieving business in many different application domains. Information search and retrieval through online tools is not only as common for most people today as making a phone call, but a critical technology for the productivity of many businesses, and a key enabler of an array of new online services. The Information Retrieval (IR) field has produced remarkable achievements since its early days, and has played a decisive part in the success of the World Wide Web. A large body of theories, methodologies, algorithms, systems, and toolkits has been developed since then, which are available today to scientists and practitioners.

After decades of research and tecnological development, the field is still under intense evolution, and keeps raising compelling challenges to the research community. The Information Retrieval Group at the Polytechnic School of the Autónoma University of Madrid conducts its research and development work in this field, with a particular focus on technologies in the personalization spectrum. Within this broad area, our activities are currently addressing the following topics:

• Personalized information search and retrieval
• Recommender systems
• IR in context
• Novelty and diversity in IR and recommender systems
• Interactive IR
• Performance prediction
• Social tags and folksonomies
• Semantics representation