About Search Engines
Last modified 1/27/07
Search Engines vs. Directories
Search engines, such as Google, create their listings automatically.
Search engines crawl through the web. Search engines eventually find your
site and index the pages they find. Page titles, body text (ie, great content),
META
tags and other elements all play a role in what gets indexed. People
then review the results of what was found by the search engine, based on
keywords they type into the search engine.
A directory such as Yahoo! Directory depends on human editors to create its listings.
You submit a description of your site to the directory for editors to
review. A good site, with good content, will be more likely to get reviewed
than a poor site. A search of a directory looks for matches only in that directory's index.
Yahoo! also has a search engine that includes spidered websites along with their directory listings and "Sponsor Results" which are pay per click ads, similar to Google's Adwords. Originally Yahoo! displayed only listings from their directory. Then in 2002 they added search engine listings from Google. In 2004 they started using their own search engine based on AltaVista's technology. A few years later they acquired Overture (formerly GoTo) which was the first pay per click program.
Other directories on the web include:
Search Engine Elements
The three major elements of a search engines are: the spider, also called
the crawler; the index or catalog; and the search engine which displays
the results of your query in your browser.
The spider visits your web page, indexes it, and then follows links to
other pages within the site. This is sometimes referred to as being "spidered"
or "crawled." The spider returns to the site every so often looking
for changes.
The index is a giant database that contains a copy of every web page
that the spider finds. When a web page is changed, then this database
is updated with the new information.
Sometimes it takes a while for pages or changes to be added to the index.
Therefore, a web page may have been "spidered" but not yet "indexed."
Until it is added to the index, it is not available to searches by the
search engine.
Search engine software sifts through the millions of pages recorded in
the index to find matches to a query and ranks them in the order of what
it believes is most relevant. Different search engines often produce very
different results.
Search Engine Tips
If you have a general subject in mind (like "coins"), type the word or
words in the Search box and click the Search button. Results are usually
listed in order of relevancy based on keywords and other factors.
Advanced Search Features
If you know exactly what you want, you can get better results by entering
very specific information into the Search box. Despite differences in
each search engine's tools, there are tools that many search engines have
in common.
- Searching for an Exact Phrase
- To require that an entire phrase be found in a search,enter quotes
(" ") around the terms. For example, "giants
baseball" returns listings where the words "giants"
and "baseball" appear together and in
that order, either in the title, the URL of the Web site, the description,
the keywords, or the document. If no sites are found that contain both
terms, sites that contain either term will be displayed.
-
- Searching For Required Words
- You can type the plus sign (+)
or the word AND before a word to
require that it be found in all of the search results. For example,
giants +baseball (include a space
between the first word and the + symbol) or giants
AND baseball returns all listings that contain "baseball"
and "giants" but not necessarily together.
-
- Searching For Excluded Words
- Use the minus sign (-) before
a word or the word NOT to require
that it not be found in the search results. For example, giants
-baseball (include a space between the first word and the
- symbol) or giants NOT baseball lists
sites containing "giants" but not "baseball."
Some engines like AND NOT (two words)
or ANDNOT (one word) better than
just NOT.
-
- Searching For Multiple Words
- Use the word OR to require
that one or the other term be found in the search results. For example,
giants OR baseball (include a space
on each side of the OR) lists sites containing "giants"
or "baseball." You can combine AND,
OR, AND NOT by using parentheses.
For example, to find documents that contain the word giants
but not either the word baseball or football
type giants NOT (baseball OR football).
You could also type this giants -(baseball
OR football). Note: You cannot begin a search with a "-"
term. You must put some other search term first.
-
- Using Wildcards
- You can use the asterisk (*) character
to indicate a wildcard search. This is useful when you are trying to
match a term that may or may not be plural or might use one of several
verb tenses. For example chemi*
will find results containing words that begin with 'chemi' (e.g. chemical,
chemistry, chemist). You must have at least four non-wildcard
characters in a word before you introduce a wildcard. This is not necessary
for plurals because a search on cat
will also return results containing the word cats,
and a search on cats will return
results containing the word cat.
Some search engines support two wildcards. The asterisk (*)
is used to replace multiple characters and the percent (%)
symbol is used to replace only one character. For example psych*ist
will find all results which contain words that begin and end
with 'psych' and 'ist' (e.g. psychologist, psychiatrist),
and gene%logy will return sites
containing words beginning with 'gene' and ending with 'logy,' separated
by a single letter (e.g. genealogy and geneology)
which is useful for commonly misspelled words. You can also use
multiple wildcards within a single word.
Major Search Engines
- AOL
Search - A Google powered search engine used by AOL users also pulls listings from
the Open Directory Project.
- AltaVista
- the Internet's first Web Index, has very comprehensive coverage and a wide
range of power searching commands, which make it a particular favorite
among researchers. It gets its listings from Yahoo! Search.
- All The Web - uses results
from Yahoo! Search plus an index of tens of millions of pdf and doc files.
- Ask.com - (formerly Ask Jeeves)
is a human-powered search service that attempts to
direct you to the exact page that answers your question. If it fails
to find a match within its own database, then it will provide web pages
from their search engine.
- Excite
- A popular web portal (a page that, in addition to search, includes news, sports, weather,
email and much more) on the web. Excite uses a metasearch engine that searches Google,
Yahoo and Ask listings.
- Google
- Currently the most popular search engine, makes heavy use of link popularity as
a primary way to rank web sites. This can be especially helpful in finding
good sites in response to general searches such as "cars" and "travel,"
because users across the web have in essence voted for good sites by
linking to them.
Google is also known for a wide range of features including: cached pages,
excellent spell checking, access to dictionary definitions, stock quotes, street maps, telephone
numbers and more. The Google Toolbar is also very popular.
- HotBot
- has advanced search features and presents listings from either Ask.com or MSN and the
Open Directory Project
- LookSmart
includes past and popular searches right on their home page. They also have a pay per click advertising program.
- Lycos
- another web portal offers "personalized content" including free email, websites,
blogs and photo sharing. They include listings from the
Open Directory Project. A good looking site.
- MSN
Search - Microsoft's MSN web portal also offers free email, instant messenger, and a
directory. It previously used Looksmart for its search results but now provides access to
Yahoo's listings.
- Netscape
Search - Netscape Search's results come primarily from Google and the
Open Directory Project.
- Open
Directory Project - Uses volunteer
editors to catalog the web. It was acquired by Netscape
in November 1998, and the company pledged that anyone would be able
to use information from the directory through an open license arrangement.
Netscape itself was the first licensee. Lycos also
uses the information for its main service and within Lycos-owned HotBot.
Here's more information about
Open Directory.
- Search.com
- A metasearch engine owned by CNET, that searches Google, Ask.com, LookSmart and dozens
of other leading search engines to bring you the best results.
- Snap
- An innovative search company that offers previews of websites in search listings.
-
WebCrawler is a metasearch engine that combines results from Google, Yahoo! Search, MSN
Search and Ask.com. They also offer a toolbar with Dictionary Search that you can download.
- Yahoo! Search
- Once the web's most popular search service is still a good alternative to Google. Yahoo is
the oldest major web site directory, having launched in late 1994.
Comparison Shopping Search Engines
- Froogle - part of the Google
family, this site is still under development.
- MSN Shopping - a Microsoft company
where you can compare over 36 million products from over 8,000 stores, all in one place.
- MySimon - owned my CNET offers
shopping recommendations, buying advice, and side by side price comparisons.
- NexTag - is the leading comparison shopping site for products, financial services, travel,
automobiles, real estate, education and more
- PriceRunner - was designed to
provide consumers with easy online access to specifications and prices.
- PriceGrabber
- TheFind.com - Our unbiased
"Product Ranking Engine" crawls over 500,000 stores to find over 150 Million products
web-wide. (Still under development in Jan 2007.)
- Shopping.com - this eBay
company pioneered online comparison shopping and today is one of the fastest growing shopping
destinations for a comprehensive set of products from thousands of trusted stores from across
the Web.
Geographic Search Engines
- Google Maps - the first of these that offered a satellite view of any part of the earth. You can use it as a map, get directions or search for web listings in a certain geographical area.
- MapQuest - my personal favorite for mapping and directions - and getting better all the time.
- Yahoo! Maps - also getting better all the time. I find the ads more annoying though.
For a more complete list of search engines, see Wikipedia's article. Another good article, written by Danny Sullivan in 2004, can be found at SearchEngineWatch.com.
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