The Web is becoming the largest data repository in the world and presents a key driving
force for a large spectrum of information technology (IT). To develop effective and intel￾ligent web applications and services, it is critical to discover useful knowledge through
analyzing large amounts of content, hidden content structures, or usage patterns of web
data resources. To achieve such a goal, a variety of techniques in diverse research areas
need to be integrated, including natural language processing, information extraction,
information retrieval, information filtering, knowledge representation, knowledge man￾agement, machine learning, databases, data mining, web mining, text mining, agent,
human–computer interaction, and the semantic web. These integrated techniques should
address the key challanges from the heterogeneous and dynamic nature of web contents
and usage patterns