The Fourth International Conference on Signal-Image Technology & Internet-Based S- tems (SITIS 2008) has been successfully held during the period 30th November to 3rd of December of the year 2008 in Bali, Indonesia. The Track Web-Based Information Te- nologies & Distributed Systems (WITDS) is one of the four tracks of the conference. The track is devoted to emerging and novel concepts, architectures and methodologies for c- ating an interconnected world in which information can be exchanged easily, tasks can be processed collaboratively, and communities of users with similar interests can be formed while addressing security threats that are present more than ever before. The track has attracted a large number of submissions; only ?fteen papers have been accepted with - ceptance rate 27%. After the successful presentations of the papers during the conference, the track chairs have agreed with Atlantis publisher to publish the extended versions of the papers in a book. Each paper has been extended with a minimum of 30% new materials from its original conference manuscript. This book contains these extendedversions as chaptersafter a second roundof reviews and improvement. The book is an excellent resource of information to researchers and it is based on four themes; the ?rst theme is on advances in ad-hoc and routing protocols, the second theme focuses on the latest techniques and methods on intelligent systems, the third theme is a latest trend in Security and Policies, and the last theme is applications of algorithms design methodologies on web based systems.