Search
Engines & Directories
Search engines help people find relevant
information on the Internet.
Major search engines maintain huge databases of
web sites that users can search by typing in some
text.
To compile their databases, search
engines rely on computer programs called
robots or spiders. These programs
crawl across the web by following links from site
to site and indexing each site they visit. Each
search engine uses its own set of criteria
& algorithms to decide what to include
in its database. Some search engines index each
page in a web site whilst others index only the
main page.
Every search engine uses its own unique algorithm,
to index and score web sites. Each engines'
algorithms weigh various factors, such as a
page's design and links, to rank pages in their
results. By constantly refining and improving
their algorithms, search engines hope to give
their visitors the most relevant results.
Major Engines &
Directories
Google http://www.google.com
Google UK http://www.google.co.uk
Google has a reputation as the first choice for
web searches. The crawler-based service provides
both comprehensive coverage of the web along with
great relevancy. Google's refined relevancy algorithms
make use of link analysis to
better propel good pages from DMOZ
database to the top. In addition, when viewing
sites by category, they will be listed in PageRank
order, which means the most popular sites based
on analyzing links from across the web will be
listed first.
Yahoo http://www.yahoo.com
Yahoo UK http://www.yahoo.co.uk
Yahoo is now powered by Google,
but adds information from its own directory which
appears to make search results more readable.
AllTheWeb http://www.alltheweb.com
An excellent crawler-based search engine which
provides both comprehensive coverage of the web
and outstanding relevancy.
Alta Vista http://www.altavista.com
http://www.altavista.co.uk
Alta Vista is the oldest crawler-based
search engine on the web. Improvements have been
made to this search engine recently but crawlers
such as Google and AllTheWeb provide more comprehensive
results.
MSN Search http://search.msn.com
MSN Search relies on search providers for answers
to many of its queries. Usually, it will be human-powered
results from the Look Smart directory that dominate
the page. MSN uses its own search algorithm to
sift through all the listings from Look Smart
to automatically find answers that are believed
to be best.
AOL Search http://aolsearch.aol.com
& http://search.aol.com
AOL Search provides users with editorial
listings that come Google's crawler-based index.
The same search on Google and AOL will come
up with very similar matches.
Ask Jeeves http://www.askjeeves.com
Ask Jeeves instead depends on crawler-based
technology to provide results to its users.
These results come from the Teoma search engine
that it owns.
HotBot http://www.hotbot.com
HotBot provides easy access to
four major crawler-based engines - AllTheWeb.com,
Google, Inktomi and Teoma.
Lycos http://www.lycos.com
Lycos is one of the oldest engines and results
are provided by AllTheWeb
Teoma http://www.teoma.com
Teoma is a crawler-based engine owned
by Ask Jeeves.
Inktomi http://www.inktomi.com
Yahoo-owned Inktomi provides results to Yahoo-rival
MSN Search.
Look Smart http://www.looksmart.com
Human-compiled directory of web sites. Look
Smart provides its results to other search engines
that need listings.
Open Directory- DMOZ http://dmoz.org
The Open Directory uses volunteer editors to
catalog the web and provides results for Google.
Overture http://www.overture.com
Overture is an extremely popular paid placement
search engine that provides ads to many of the
engines listed on this page.
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