This book constitutes revised selected papers from  the 12th International Conference on Web Information Systems and Technologies, WEBIST 2016, held in Rome, Italy, April 23-25, 2016, organized by the Institute for Systems and Technologies of Information, Control and Communication (INSTICC). 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 9 full papers presented in this volume were carefully reviewed and selected originally 123 paper submissions. They contribute to the understanding of relevant trends of current research on Web Information Systems and Technologies, comprising recommender systems, sentiment analysis, ranking, and Web applications and Web architecture.