Application of data mining techniques to the World Wide Web, referred to as Web mining, has been the focus of several recent research projects and papers. The term Web mining has been used in two distinct ways. The first, called Web content mining is the process of information discovery from sources across the World Wide Web. The second, called Web usage mining, is the process of mining for user browsing and access patterns. Web usage mining attempts to discover useful knowledge from the secondary data obtained from the interactions of the users with the Web. Web usage mining has become very critical for effective Web site management, business and support services, personalization, and network traffic flow analysis and so on.