Information Retrieval on the web. There are additional requirements
such as the need to crawl and maintain an index. And there are
additional structural advantages, such as links, tags, metadata, and
social structure. For example, certain HTML tags provide more emphasis
to their contents than do other. The use of hyperlinking adds a new
level of associations between documents. The words around anchor tags
can be used to describe the document that is linked, and the links on
a page can in turn describe itself. Unique phrases can be used to
create a strong relationship to a page more easily than a common
phrase. Hyperlinks can be used to establish a community of trust.
-Thomas Hayden
