4. • Program that identifies a database
• Corresponds to keywords specified by user
• To find particular sites on World Wide Web
5.
6. • It works by sending out a spider to fetch documents
• An indexer then reads these documents and creates an
index based on the words contained in each document
7.
8. • The first full featured search engine was WebCrawler
project that started in 1994
• The Lycos and Alta Vista appeared in 1995 and
for many years was the major player in the field
9. • In 1997, Sergey Brin and Larry Page
created Google as a research project at Stanford University
• Google is now the most popular search engine in the world
13. • CRAWLERS:
• It uses a "spider" or a "crawler" to search the Internet
• It digs through individual web pages, pulls out keywords
• Then adds the pages to the search engine's database
• EXAMPLES:
• Google
• Yahoo!
14. • DIRECTORIES:
• Directories are human powered search engines
• A website is submitted to the directory and
must be approved for inclusion by editorial staff
• EXAMPLES:
• Open directory project
• The internet public directory
15. • HYBRID:
• Hybrids are a mix of crawlers and directories
• Sometimes, you have a choice when you search whether to
search the Web or a directory
• Other times, you may receive both human powered results
& crawler results for the same search
• The human results are usually listed first
16. • META:
• Search several other search engines at once
• Combines the results into one list
• While you get more results with meta search engines,
the relevancy and quality of the results may
sometimes suffer
• EXAMPLES:
• Dogpile
• Clusty
