Entity Grouping for Accessing Social Streams via Word Clouds.- Compatibility Checking of REST API based on Coloured Petri Net.- Augmented ODV: Web-driven Annotation and InteractivityEnhancement of 360 Degree Video in Both 2D and 3D.- CrySIL: Bringing Crypto to the Modern User.- Motivating Online Teams: An Investigation on Task Significance, Coordination and Incentive Mechanisms.- Measuring Friendship Strength in Online Social Networks.- Enhancing the Modularity and Flexibility of Identity Management Architectures for National and Cross-border eID Applications.- A Personalized and Context-aware News Offer for Mobile Devices.- Improving Predictions with an Ensemble of Linguistic Approach and Matrix Factorization.- When Users with Preferences Different from Others get Inaccurate Recommendations.- Exploiting Temporal Dimension in Tensor-based Link Prediction.- Extracting Product Offers from e-Shop Websites.- A Comprehensive Analysis of the First Ten Editions of the WEBIST Conference.- Translation of Heterogeneous Databases into RDF, and Application to the Construction of a SKOS Taxonomical Reference.- Pre-trip Ratings and Social Networks User Behaviors for Recommendations in Touristic Web Portals.- A Transformation Language for RDF based on SPARQL.- A Sustainable Architecture for Secure and Usable Mobile Signature Solutions. 

This book constitutes revised selected papers from the 11th International Conference on Web Information Systems and Technologies, WEBIST 2015, held in Lisbon, Portugal, May 20-22, 2015, organized by the Institute for Systems and Technologies of Information, Control and Communication (INSTICC), and technically sponsored by the European Research Center for Information Systems (ERCIS). The purpose of the WEBIST series of conferences is to bring together researches, engineers and practitioners interested in technological advances and business applications of web-based information systems. The 17 full papers presented in this volume were carefully reviewed and selected originally 115 paper submissions. They were organized in topical sections names: web interfaces and applications; internet technology; society, e-business and e-government; web intelligence; and mobile information systems.