Keyword-Based Search Engines

The World Wide Web (WWW), also known as the Web, was introduced in 1992 at the Center for European Nuclear Research (CERN) in Switzerland [28]. What began as a means of facilitating data sharing in different formats among physicists at CERN is today a mammoth, heterogeneous, non-administered, distributed, global information system that is revolutionizing the information age. The Web is organized as a set of hypertext documents interconnected by hyperlinks, used in the Hypertext Markup Language (HTML) to construct links between documents. The many potential benefits the Web augurs have spurred research in information search/filtering [54, 154], Web/database integration [43, 168], Web querying systems [3, 150, 155, 187], and data mining [66, 252]. The Web has also brought together researchers from areas as diverse as communications, electronic publishing, language processing, and databases, as well as from multiple scientific and business domains.