Proceedings of the 2nd International Workshop on Semantic Adaptive Social Web (SASWeb 2011) co-located with the 19th User Modeling, Adaptation and Personalization Conference (UMAP 2011) July 15, 2011, Girona, Spain http://semantic-adaptive-social-web.uniud.it/events/2011/sasweb/ Copyright © 2011 for the individual papers by the papers' authors. Copying permitted only for private and academic purposes. Re-publication of material from this volume requires permission by the copyright owners. This volume is published and copyrighted by Federica Cena, Antonina Dattolo, Ernesto William De Luca, Pasquale Lops, Till Plumbaum, and Julita Vassileva. ISSN 1613-0073 Organizing Committee  Federica Cena University of Turin, Italy.  Antonina Dattolo University of Udine, Italy.  Ernesto William De Luca Technische Universität Berlin, Germany.  Pasquale Lops University of Bari Aldo Moro, Italy.  Till Plumbaum Technische Universität Berlin, Germany.  Julita Vassileva University of Saskatchewan, Canada. Program Committee  Liliana Ardissono Università degli Studi di Torino, Italy  Lora Aroyo University of Amsterdam, Holland  Shlomo Berkovsky CSIRO, TasICT Centre, Australia  Peter Brusilovsky University of Pittsburgh, USA  David Bueno Vallejo Universidad de Málaga, Spain  Ivan Cantador Universidad Autónoma de Madrid, Spain  Francesca Carmagnola University of Turin, Italy  Pablo Castells Universidad Autónoma de Madrid, Spain  Cristina Gena University of Turin  Marco de Gemmis University of Bari Aldo Moro, Italy  Darina Dicheva Winston Salem University , USA  Vania Dimitrova University of Leeds, UK  Tom Heath Talis Information Ltd, United Kingdom  Eelco Herder L3S Research Center, Germany  Andreas Hotho University of Würzburg, Germany  Gilles Hubert IRIT, Toulouse, France  Geert-Jan Houben TU Delft, Holland  Dietmar Jannach Dortmund University of Technology  Tsvi Kuflik University of Haifa, Israel  Vincenzo Loia University of Salerno, Italy  Luca Mazzola ITC, University of Lugano, Switzerland  Alessandro Micarelli University “Roma Tre”, Roma, Italy  Cecile Paris CSIRO ICT Centre, Australia  Francesco Ricci Free University of Bozen-Bolzano, Italy  Giovanni Semeraro University of Bari Aldo Moro, Italy  Sergey Sosnovsky German Research Center for AI, Saarbrucken, Germany  Armando Stellato University of Tor Vergata, Rome  Ilaria Torre University of Turin  Markus Zanker University Klagenfurt, Austria  Torsten Zesch Technical University of Darmstadt, Germany Preface Social Web (also called Web 2.0) is growing daily, together with the number of users and applications. In this way, users generate a significant part of Web content and traffic: they create, connect, comment, tag, rate, remix, upload/download, new or existing resources in an architecture of participation, where user contribution and interaction add value. Users are also involved in a broad range of social activities like creating friendship relationships, recommending and sharing resources, suggesting friends, creating groups and communities, commenting friends activities and profiles and so on. At the same time, Semantic Web (also called Intelligent Web), whose main goal is to describe Web resources in a way that allows machines to understand and process them, has started to go out from academies and begins to be exploited in many web sites, incorporating high-quality user contributed content and semantic annotations using Internet-based services as an enabling platform. The recent advances in the Semantic Web area, and specifically the widespread use of weak semantic techniques (the so-called ‘lowercase’ semantic web), such as the use of microformats (e.g. eRDF, RDFa) to attach semantics to content, also provide new standardized ways to process and share information. This approach allows information intended for end-users (such as contact information, geographic coordinates, calendar events) to also be automatically processed by machines, and this obviates other more complicated methods of processing, such as natural language processing or screen scraping. In this workshop we are interested to analyze the benefits adaptation and personalization have to offer in the Web of the future, the so called Social Semantic Web or Web 3.0, that puts together Semantic Web and Social Web. The workshop aims at discussing the state-of-the-art, open problems, challenges and innovative research approaches in adaptation and personalization for the Social Semantic Web. It provides a forum for proposing innovative and open models, applications and new data sharing scenarios, as well as novel technologies and methodologies for creating and managing these applications. Examples of stimulating application fields are social bookmarking environments, publication sharing systems, intelligent cultural guides, collaborative working, social networking sites, digital libraries, e-learning and recommender systems. We would like to thank all the authors for their submissions, and our Program Committee and additional reviewers for their precious work. June 2011 Federica Cena Antonina Dattolo Ernesto William De Luca Pasquale Lops Till Plumbaum Julita Vassileva SASWeb 2011 Workshop Chairs Table of Contents Visualizing and Managing Folksonomies Antonina Dattolo, Emanuela Pitassi Selective Propagation of Social Data in Decentralized Online Social Network Udeep Tandukar, Julita Vassileva Towards a Followee Recommender System for Information Seeking Users in Twitter Marcelo G. Armentano, Daniela Godoy, Analía Amandi Adaptive Faceted Search on Twitter Ilknur Celik, Fabian Abel, Patrick Siehndel cTag: Semantic Contextualisation of Social Tags Ignacio Fernández-Tobías, Iván Cantador, Alejandro Bellogín Social Semantic Web Fosters Idea Brainstorming Matteo Gaeta, Vincenzo Loia, Giuseppina Rita Mangione, Francesco Orciuoli, Pierluigi Ritrovato Recommending #-Tags in Twitter Eva Zangerle, Wolfgang Gassler, Gunther Specht