World Wide Web Search Services

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Searching web pages is one of the most frustrating and problematic tasks performed on the WWW. The situation is getting worse because of

• the Web’s fast growing size (at least 3.74 billion indexed pages as of 07/17/2023) and lack of structural style (semi-structured HTML) and


• the inadequacy of existing web search engine technologies.

Traditional search techniques are based on users typing in search keywords which the search services can then use to locate the desired web pages. This approach has two major problems:

• It normally retrieves too many documents, of which only a small fraction are relevant to the users’ needs.


• Furthermore, the most relevant documents do not necessarily appear at the top of the query output list.

Search Engines
On the Internet, a search engine is a coordinated set of programs that traditionally consists of three components:

Crawlers visit and read every page on web sites, using hypertext links on each page to discover and read a site’s other pages. Web page indexes are created from the pages that have been read.

• Search and ranking software receives user’s search request, compares it to the entries in the index, and returns results to the user.