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The Internet: How search engines index and rank pages. Sources: How Search Engines Rank Web Pages By


Search engines crawl the web, then people search through what they have found. ... A directory such as Yahoo depends on humans for its listings. ... – PowerPoint PPT presentation

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Title: The Internet: How search engines index and rank pages. Sources: How Search Engines Rank Web Pages By

The Internet How search engines index and
rank pages. Sources How Search Engines Rank
Web Pages By Danny Sullivan, Editorhttp//searchen
Question 1
  • What is the difference between a search engine
    and a directory?

Search Engines
  • Search engines, such as Google, create their
    listings automatically. Search engines crawl the
    web, then people search through what they have

  • If you change your web pages, search engines
    eventually find these changes, and that can
    affect how you are listed. Page titles, body copy
    and other elements all play a role.

  • A directory such as Yahoo depends on humans for
    its listings.
  • You submit a short description to the directory
    for your entire site, or editors write one for
    sites they review. A search looks for matches
    only in the descriptions submitted.

Question 2
  • List and define the three major elements of a
    search engine?

Part I
  • Search engines have three major elements. First
    is the spider, also called the crawler. The
    spider visits a web page, reads it, and then
    follows links to other pages within the site.
    This is what it means when someone refers to a
    site being "spidered" or "crawled."

Spider -continued-
  • The spider returns to the site on a regular
    basis, such as every month or two, to look for

Part II The Index
  • The index, sometimes called the catalog, is like
    a giant book containing a copy of every web page
    that the spider finds. If a web page changes,
    then this book is updated new information.

Part III Search engine software
  • Search engine software is the third part of a
    search engine. This is the program that sifts
    through the millions of pages recorded in the
    index to find matches to a search and rank them
    in order of what it believes is most relevant.

Question 3
  • Why does the same search conducted on different
    search engines yield different results?

Question 3
  • All search engines have the basic parts described
    above, but there are differences in how these
    parts are tuned. That is why the same search on
    different search engines often produces
    different results.

Question 4
  • How do search engines rank pages?

How Search Engines Ranks Pages
  • So how do search engines go about determining
  • They follow a set of rules, with the main rules
    involving the location and frequency of keywords
    on a web page. Call it the location/frequency
    method, for short.

Location, Location, Location...and Frequency
  • Pages with keywords appearing in the title are
    assumed to be more relevant than others to the
  • Search engines will also check to see if the
    keywords appear near the top of a web page, such
    as in the headline or in the first few paragraphs
    of text.
  • They assume that any page relevant to the topic
    will mention those words right from the

Spice in the Recipe
  • Frequency is the other major factor in how search
    engines determine relevancy.
  • A search engine will analyze how often keywords
    appear in relation to other words in a web page.
  • Those with a higher frequency are often deemed
    more relevant than other web pages.

  • some search engines index more web pages than
  • Some search engines also index web pages more
    often than others.
  • The result is that no search engine has the exact
    same collection of web pages to search through.

  • Search engines may also give web pages a "boost"
    for certain reasons.
  • Some search engines use link popularity as part
    of its ranking method. It can tell which of the
    pages in its index have a lot of links pointing
    at them.
  • These pages are given a slight boost during
    ranking, since a page with many links to it is
    probably well-regarded on the Internet.

  • Some hybrid search engines, those with associated
    directories, may give a relevancy boost to sites
    they've reviewed
  • The logic is that if the site was good enough to
    earn a review, chances are its more relevant
    than an unreviewed site.

Meta Tags
  • Meta tags are what many web designers mistakenly
    assume are the "secret" to propelling their web
    pages to the top of the rankings.
  • Some do give a slight boost to pages with
    keywords in their meta tags. read them at all,
    and there are plenty of examples where pages
    without meta tags still get highly ranked. They
    can be part of the recipe, but they are not
    necessarily the secret ingredient.

  • Search engines may also penalize pages or exclude
    them from the index, if they detect search engine
  • An example is when a word is repeated hundreds of
    times on a page, to increase the frequency and
    propel the page higher in the listings.
  • Search engines watch for common spamming methods
    in a variety of ways, not the least by following
    up on complaints.

Question 5
  • Define the following terms

  • Bookmark - A page on the Netscape Browser that
    lists URLs or Web addresses. Bookmarks serve as
    links for easy access to Web addresses. MS
    Explorers equivalent is called Favorite

  • To bookmark a Web page on your screen, click
    Bookmark on the bar, and when it is displayed,
    click Add Bookmark. The link then adds to the
    bottom of the Bookmark Listing.

Boolean Search
  • Boolean Search - A keyword search that uses
    Boolean Operators for obtaining a precise
    definition of a query. See Operators Used In
    Keyword Searches in Section B
  • and, or, not etc..

  • Browser - A computer program used to connect to
    Web sites on the World Wide Web and access
  • Examples Netscape Navigator, Microsoft Internet

Directory Search
  • Directory Search - A hierarchical search starts
    with a general heading and proceeds through
    selection of increasingly more specific headings
    or subjects.

Directory Search
  • It provides a means of focusing more closely on
    the object of the search. It is also referred to
    as subject search, directory guide or directory

Home Page
  • Home Page - The first page of a search tools Web

Hypertext Link
  • Hypertext Link - A highlighted word or image
    shown in color on a Web page that when clicked
    connects or links to another location with
    related information. Links provide an easy way
    to move about the Internet.

  • Internet - The Internet, with a large I, refers
    to a worldwide system of linked computer networks
    that serve as a communication system. When used
    with a small i, a term used to mean a group of
    interconnected local networks.

Keyword Search
  • Keyword - A term that a computer can recognize
    and use as the basis for executing a search.
  • Keyword Search - A search that utilizes terms
    that defines the users interest.

  • Query - A search request. A combination of words
    and symbols that defines the information that the
    user is seeking. Queries are used to direct
    search tools to appropriate Web sites to obtain

  • Ranking - A means of listing hits in the order of
    their relevancy. It is usually determined by some
    selection of the number, location and frequency
    of the term in the document being searched.

Search Engine.
  • Search Engine - A host computer that serves a Web
    site and provides information from within its own
    sites and via links with other Web sites. This is
    accomplished by using the keywords of a query to
    match index terms in the search engines

Search Tool
  • Search Tool - A computer program which conducts a
    search on the World Wide Web.

  • Uniform Resource Locator URL -Uniform Resource
    Locator is the Internet designation of a Web

  • World Wide Web WWW or the Web - A global
    computer communication system that uses the
    Internet to transmit data i.e. text, numbers,
    images and sound.

Question 6
  • What is a meta-search? How does it work?
  • A multi-engine search, also called a meta-search,
    utilizes a number of search engines

  • The search is conducted via keywords employing
    commonly used operators or plain language. It
    then lists the hits either by search engine or by
    integrating the results into a single listing.
  • Tip Use to speed up the search process.
  • Advantage Often provides fewer references and is
    tolerant of imprecise search questions.
  • Disadvantage Can not be used as effectively as a
    search engine to conduct difficult searches.

Question 7
  • How are the following notations useful in search
    engines that have a common set of operators? ,
    -, " , AND, OR, NOT.