Web search: how the Web has changed information retrieval

Topical metadata are simultaneously hailed as building blocks of the semantic Web and derogated as spam. The significance of the metadata controversy depends on the technological appropriateness of adding them to Web pages. A survey of Web technology suggests that Web pages are both transient and volatile: poor hosts of topical metadata. A more supportive environment exists in the closed Web. The vast majority of Web pages, however, exist in the open Web, an environment that challenges the application of legacy information retrieval concepts and methods.