This document provides an overview of key concepts for understanding how search engines work. It defines search engines as computer programs that use clusters of computers to search the web and index pages based on important words found. Search engines allow users to search their indexes by entering keywords or browsing categorized directories. The document discusses how search engines build their indexes by crawling websites, and how they rank pages based on factors like keyword frequency, location, and link popularity. It also notes that search results vary between engines and are personalized based on individual search histories.

1. EDU 626 Integration of Educational Technology
Spring 2012
Lost in the net?
Navigating Search Engines

2. Define “search engine”?
 What is a search engine?
− Essentially, a search engine is a computer
program. The biggest ones, such as Google,
Microsoft’s Bing, Yahoo!, and Ask, use giant
clusters of computers to search the web.
Others search only the owner's site
• http://www.bbc.co.uk/webwise/guides/about-search-engines

3. A more scholarly definition
 search engine
− Originally, a hardware device designed to
search a text-based database for specific
character strings (queries) typed as input by the user.
More recently, computer software designed to help the
user locate information available at sites on the World
Wide Web by selecting categories from a hierarchical
directory of subjects (example: Yahoo!) or by entering
appropriate keywords or phrases (Google, Hotbot, etc.).
Most Web search engines allow the searcher to use
Boolean logic and truncation in search statements.
• Online Dictionary for Library and Information Science

4. Huh?
 What’s the core of that definition?
− “designed to help the user locate information
available at sites on the World Wide Web”
− Two methods involved to locate that
information:
1. from a hierarchical directory of subjects
2. by entering appropriate keywords or phrases

5. A hierarchical directory of subjects?

6. Example of a web directory?
Historically, t
hat is! But is
Yahoo! a
directory
now?

7. Another example—that exists today!
HotVsNot.com is a
premium web
directory focused
on providing high-
quality, well-
categorized listings
of business-related
websites.
http://www.hotvsnot.
com/About/
http://www.hotvsnot.com/

8. Entering appropriate keywords or phrases
 What is a keyword?
− A “keyword” or “keyword Phrase” is the word
or words a person types into the search box on a
search engine to look up subject matter on the
Internet. If you are looking for a flag for your
home or office, you might type in “American
Flags”.
• SEO Questions & Answers (FAQ)

9. How does a search engine work?
 3 basic tasks of search engines:
1. They search the Internet -- or select pieces of the
Internet -- based on important words.
2. They keep an index of the words they find, and
where they find them.
3. They allow users to look for words or
combinations of words found in that index.
• How Internet Search Engines Work
by Curt Franklin

10. How a
search
engine
builds its
index

11. What does this mean?
1. You are not searching the Web directly, and
not even a snapshot of the Web, either
2. You are not even searching all of the Web,
only the websites that have been crawled by
the search engine’s bots
3. The indexes do not distinguish the keywords
by their meaning—they’re simply a collection
of words with the links to where they occur
[not for nothing is one of the metasearch
engines called Dogpile!]

12. What about the order of appearance?
 How Search Engines Rank Web Pages
1. Frequency of Keywords
• Search Engines look for the frequency of keyword
repeats in the content of the web page and the web
pages with the best keyword frequency stand a chance
to get to the top of search engine results. Low
keyword frequency may result in loss of ranking and
deliberate use of excessive keywords will end up being
penalized by search engines. SEO [Search Engine
Optimization] experts recommend keyword density of
3 to 5% of the whole content of the web page.
• January 4, 2012 By admin

13. Other ranking methods
 How Search Engines Rank Web Pages
2. Location of Keywords
• Search Engines assume that the most relevant
keywords of the content should be present in the
headline, top of the webpage & bottom of the
webpage.
• Using your primary keywords in the Title & in the
beginning and end of the content optimizes your web
page for the Search Engines.

14. Other ranking methods
 How Search Engines Rank Web Pages
3. Link Popularity
• Search Engines analyze links found on web pages and
how pages link to each other to determine the
popularity & importance of a web page.
4. Click-Through Rate
• Search Engines may pull down high ranking web
pages if they find that the web pages are not
attracting enough clicks and the web pages ranking
down the order is attracting more visitor clicks. If
your website is attracting more clicks than the
websites ranking first in the search engines, your
website will get ranking boost.

15. Can you improve your site’s ranking?
 What Is SEO / Search Engine Optimization?
− SEO stands for “search engine optimization.” It is
the process of getting traffic from the “free,”
“organic,” “editorial” or “natural” listings on search
engines. All major search engines such as
Google, Yahoo and Bing have such results, where
web pages and other content such as videos or local
listings are shown and ranked based on what the
search engine considers most relevant to users.
Payment isn’t involved, as it is with paid search ads.

16. What does all this mean?
 Your mileage will vary!
− When you compare your search across different
search engines

17. Results vary for the same search engine, too!
 Google Now Personalizes
Everyone’s Search Results
− By watching what you click on in search results, Google
can learn that you favor particular sites. For example, if
you often search and click on links from Amazon that
appear in Google’s results, over time, Google learns that
you really like Amazon. In reaction, it gives Amazon a
ranking boost. That means you start seeing more Amazon
listings, perhaps for searches where Amazon wasn’t
showing up before.
− In particular, we now have two “flavors” of personalized
search, or “Web History” as is the official Google name
for it. There’s Signed-Out Web History and Signed-In
Web History.
• Dec 4, 2009 at 6:18pm ET by Danny Sullivan

18. Limiting your search results
 Phrase search

19. Focusing your search queries
 Field Search
− Field searching is an optional way to focus your
search results. With general search engines,
you're searching the full text of many millions of
pages, and field searching can help you retrieve
results that may be more manageable. For
example, you can search for words that appear
within a particular Web site, within the URL
(Web address), in the page title, and so on. The
exact technique for doing this can differ among
search engines, so be sure to check out the Help
pages before proceeding.
• Basic Search Techniques

20. Field search commands
 Title field
− Google allintitle:
− Bing intitle:
− Searches for keywords only in the title of a
website
− e. g. allintitle:hurricane caribbean deaths
− intitle:hurricane caribbean deaths
 Limit to specific website
− Both Google and Bing use site:
− e. g. site:nasa.gov

21. Search Tutorials
http://www.sc.edu/beaufort/library/pages/bones/bones.shtml

22. Another “short and easy” tutorial
http://www.pandia.com/goalgetter/

23. A video tutorial

24. An animated search tutorial
http://library.acadiau.ca/tutorials/websearching/

25. The End