This book contains the best papers from the first two instances of the International Conference on Web Information Systems and Technologies (WEBIST 2005 and 2006), organized by the Institute for Systems and Technologies of Information, C- trol and Communication (INSTICC) in collaboration with the OMG (Object M- agement Group), held in Miami (USA) and Setúbal (Portugal) respectively. The purpose of WEBIST is to bring together researchers, engineers and practit- ners interested in the technological advances and business applications of web-based information systems. It has four main topic areas, covering different aspects of Web Information Systems, including Internet Technology, Web Interfaces and Appli- tions, Society, e-Business, e-Government and e-Learning. WEBIST received submissions from more than 40 countries in all continents. We are happy to note that from 110 submissions in 2005 WEBIST grew to 218 paper submissions in 2006, an increase of practically 100%. After a double-blind review process, with the help of more than 120 experts from the international program c- mittee, and also after presentation at the conference, 25 papers were finally selected to be published and presented in this book.