DS4: A distributed social and semantic search systemDS4: A distributed social and semantic search system Περίληψη Δημοσίευσης σε Συνέδριο Conference Paper Abstract 2015-11-012013enWe present DS4, a Distributed Social and Semantic Search System that allows users to share and search for content among friends and clusters of users that specialise on the query topic. In DS4, nodes that are semantically, thematically, or socially similar are automatically discovered and logically organised into groups. Content retrieval is then performed by routing the user query towards social friends and clusters of nodes that are likely to answer the query. In this way, search receives two facets: the social facet, addressing friends, and the semantic facet, addressing nodes that are semantically close to the query topic. DS4 is scalable (requires no centralised component), privacy-aware (users main- tain ownership and control over their content), automatic (requires no intervention by the user), general (works for any type of content), and adaptive (adjusts to changes of user content or interest). In this work, we report our effort to design the next generation of social networks that will offer open and adaptive design, privacy-aware content management, and user-centered network creation.http://creativecommons.org/licenses/by/4.0/832-83635th European Conference on Information Retrieval Advances in Information Retrieval Petrakis Evripidis Πετρακης Ευριπιδης Dionisis Kontominas Paraskevi Raftopoulou Christos Tryfonopoulos Springer Verlag