A WEB SEARCH ENGINE is a software system that is designed to search
for information on the World Wide Web. The search results are
generally presented in a line of results often referred to as search
engine results pages (SERPs). The information may be a mix of web
pages , images, and other types of files. Some search engines also
mine data available in databases or open directories . Unlike web
directories , which are maintained only by human editors, search
engines also maintain real-time information by running an algorithm on
a web crawler .
* 1 History
* 2 How web search engines work
* 3 Market share
* 3.1 East Asia and Russia
* 3.2 Europe
* 4 Search engine bias
* 5 Customized results and filter bubbles
* 6 Christian, Islamic and Jewish search engines
* 7 Search engine submission
* 8 See also
* 9 References
* 10 Further reading
* 11 External links
Timeline of web search engines
TIMELINE (FULL LIST )
Inactive, redirects to Disney
Inactive, redirected to Yahoo!
Active, Launched as a directory
Inactive, acquired by Yahoo!
Active (rebranded ask.com)
Active also as Startpage
Active as Bing
Inactive (merged with NATE)
Inactive (URL redirected to Yahoo!)
Active, rebranded Yellowee.com
Inactive, redirects to Ask.com
Active, Launched own web search
Yahoo! Directory, 1995)
Inactive, redirects to Sogou
Active as Bing, Launched as
Inactive (redirects to Bing)
Inactive (redirects to Ecosia)
Active, Launched as
Inactive due to a lack of funding
Inactive, sold to IBM
Active, P2P web search engine
Active, Vietnamese search engine
Active, Kurdish / Sorani search engine
Active, Browser integrated search engine
Internet search engines themselves predate the debut of the Web in
December 1990. The Who is user search dates back to 1982 and the
Knowbot Information Service multi-network user search was first
implemented in 1989. The first well documented search engine that
searched content files, namely
FTP files was Archie, which debuted on
10 September 1990.
Prior to September 1993 the World Wide Web was entirely indexed by
hand. There was a list of webservers edited by
Tim Berners-Lee and
hosted on the
CERN webserver. One historical snapshot of the list in
1992 remains, but as more and more web servers went online the
central list could no longer keep up. On the NCSA site, new servers
were announced under the title "What's New!"
The first tool used for searching content (as opposed to users) on
Internet was Archie . The name stands for "archive" without the
"v". It was created by
Alan Emtage , Bill Heelan and J. Peter Deutsch,
computer science students at
McGill University in
Montreal . The
program downloaded the directory listings of all the files located on
File Transfer Protocol ) sites, creating a
searchable database of file names; however, Archie Search Engine did
not index the contents of these sites since the amount of data was so
limited it could be readily searched manually.
The rise of Gopher (created in 1991 by
Mark McCahill at the
University of Minnesota
University of Minnesota ) led to two new search programs, Veronica and
Jughead . Like Archie, they searched the file names and titles stored
in Gopher index systems. Veronica (Very Easy Rodent-Oriented Net-wide
Index to Computerized Archives) provided a keyword search of most
Gopher menu titles in the entire Gopher listings. Jughead (Jonzy's
Universal Gopher Hierarchy Excavation And Display) was a tool for
obtaining menu information from specific Gopher servers. While the
name of the search engine "Archie Search Engine " was not a reference
to the Archie comic book series, "Veronica " and "Jughead " are
characters in the series, thus referencing their predecessor.
In the summer of 1993, no search engine existed for the web, though
numerous specialized catalogues were maintained by hand. Oscar
Nierstrasz at the
University of Geneva
University of Geneva wrote a series of
that periodically mirrored these pages and rewrote them into a
standard format. This formed the basis for
W3Catalog , the web's first
primitive search engine, released on September 2, 1993.
In June 1993, Matthew Gray, then at MIT , produced what was probably
the first web robot , the
World Wide Web Wanderer , and
used it to generate an index called 'Wandex'. The purpose of the
Wanderer was to measure the size of the World Wide Web, which it did
until late 1995. The web's second search engine
Aliweb appeared in
Aliweb did not use a web robot , but instead depended
on being notified by website administrators of the existence at each
site of an index file in a particular format.
NCSA\'s Mosaic™ -
Mosaic (web browser) wasn't the first Web
browser. But it was the first to make a major splash. In November
1993, Mosaic v 1.0 broke away from the small pack of existing browsers
by including features—like icons, bookmarks, a more attractive
interface, and pictures—that made the software easy to use and
appealing to "non-geeks."
JumpStation (created in December 1993 by
Jonathon Fletcher ) used a
web robot to find web pages and to build its index, and used a web
form as the interface to its query program. It was thus the first WWW
resource-discovery tool to combine the three essential features of a
web search engine (crawling, indexing, and searching) as described
below. Because of the limited resources available on the platform it
ran on, its indexing and hence searching were limited to the titles
and headings found in the web pages the crawler encountered.
One of the first "all text" crawler-based search engines was
WebCrawler , which came out in 1994. Unlike its predecessors, it
allowed users to search for any word in any webpage, which has become
the standard for all major search engines since. It was also the first
one widely known by the public. Also in 1994,
Lycos (which started at
Carnegie Mellon University
Carnegie Mellon University ) was launched and became a major
Soon after, many search engines appeared and vied for popularity.
These included Magellan ,
Infoseek , Inktomi , Northern Light
Yahoo! was among the most popular ways for people to
find web pages of interest, but its search function operated on its
web directory , rather than its full-text copies of web pages.
Information seekers could also browse the directory instead of doing a
Netscape was looking to give a single search engine an
exclusive deal as the featured search engine on Netscape's web
browser. There was so much interest that instead
Netscape struck deals
with five of the major search engines: for $5 million a year, each
search engine would be in rotation on the
Netscape search engine page.
The five engines were Yahoo!, Magellan, Lycos, Infoseek, and Excite.
Google adopted the idea of selling search terms in 1998, from a small
search engine company named goto.com . This move had a significant
effect on the SE business, which went from struggling to one of the
most profitable businesses in the internet.
Search engines were also known as some of the brightest stars in the
Internet investing frenzy that occurred in the late 1990s. Several
companies entered the market spectacularly, receiving record gains
during their initial public offerings . Some have taken down their
public search engine, and are marketing enterprise-only editions, such
as Northern Light. Many search engine companies were caught up in the
dot-com bubble , a speculation-driven market boom that peaked in 1999
and ended in 2001.
Around 2000, Google\'s search engine rose to prominence. The company
achieved better results for many searches with an innovation called
PageRank , as was explained in the paper Anatomy of a Search Engine
Sergey Brin and
Larry Page , the later founders of Google.
This iterative algorithm ranks web pages based on the number and
PageRank of other web sites and pages that link there, on the premise
that good or desirable pages are linked to more than others. Google
also maintained a minimalist interface to its search engine. In
contrast, many of its competitors embedded a search engine in a web
portal . In fact,
Google search engine became so popular that spoof
engines emerged such as
Mystery Seeker .
Yahoo! was providing search services based on Inktomi's
Yahoo! acquired Inktomi in 2002, and
AlltheWeb and AltaVista) in 2003.
Yahoo! switched to Google's
search engine until 2004, when it launched its own search engine based
on the combined technologies of its acquisitions.
Microsoft first launched
MSN Search in the fall of 1998 using search
results from Inktomi. In early 1999 the site began to display listings
Looksmart , blended with results from Inktomi. For a short time
MSN Search used results from
AltaVista instead. In 2004,
Microsoft began a transition to its own search technology, powered by
its own web crawler (called msnbot ).
Microsoft's rebranded search engine, Bing , was launched on June 1,
2009. On July 29, 2009,
Microsoft finalized a deal in which
Yahoo! Search would be powered by
Microsoft Bing technology.
HOW WEB SEARCH ENGINES WORK
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A search engine maintains the following processes in near real time:
Web search engines get their information by web crawling from site to
site. The "spider" checks for the standard filename robots.txt ,
addressed to it, before sending certain information back to be indexed
depending on many factors, such as the titles, page content,
Cascading Style Sheets
Cascading Style Sheets (CSS), headings, as evidenced by
HTML markup of the informational content, or its metadata
HTML meta tags .
Indexing means associating words and other definable tokens found on
web pages to their domain names and HTML-based fields. The
associations are made in a public database, made available for web
search queries. A query from a user can be a single word. The index
helps find information relating to the query as quickly as possible.
Some of the techniques for indexing, and caching are trade secrets,
whereas web crawling is a straightforward process of visiting all
sites on a systematic basis.
Between visits by the spider, the cached version of page (some or all
the content needed to render it) stored in the search engine working
memory is quickly sent to an inquirer. If a visit is overdue, the
search engine can just act as a web proxy instead. In this case the
page may differ from the search terms indexed. The cached page holds
the appearance of the version whose words were indexed, so a cached
version of a page can be useful to the web site when the actual page
has been lost, but this problem is also considered a mild form of
linkrot . High-level architecture of a standard
Typically when a user enters a query into a search engine it is a few
keywords . The index already has the names of the sites containing
the keywords, and these are instantly obtained from the index. The
real processing load is in generating the web pages that are the
search results list: Every page in the entire list must be weighted
according to information in the indexes. Then the top search result
item requires the lookup, reconstruction, and markup of the snippets
showing the context of the keywords matched. These are only part of
the processing each search results web page requires, and further
pages (next to the top) require more of this post processing.
Beyond simple keyword lookups, search engines offer their own GUI- or
command-driven operators and search parameters to refine the search
results. These provide the necessary controls for the user engaged in
the feedback loop users create by filtering and weighting while
refining the search results, given the initial pages of the first
search results. For example, from 2007 the Google.com search engine
has allowed one to filter by date by clicking "Show search tools" in
the leftmost column of the initial search results page, and then
selecting the desired date range. It's also possible to weight by
date because each page has a modification time. Most search engines
support the use of the boolean operators AND, OR and NOT to help end
users refine the search query .
Boolean operators are for literal
searches that allow the user to refine and extend the terms of the
search. The engine looks for the words or phrases exactly as entered.
Some search engines provide an advanced feature called proximity
search , which allows users to define the distance between keywords.
There is also concept-based searching where the research involves
using statistical analysis on pages containing the words or phrases
you search for. As well, natural language queries allow the user to
type a question in the same form one would ask it to a human. A site
like this would be ask.com.
The usefulness of a search engine depends on the relevance of the
result set it gives back. While there may be millions of web pages
that include a particular word or phrase, some pages may be more
relevant, popular, or authoritative than others. Most search engines
employ methods to rank the results to provide the "best" results
first. How a search engine decides which pages are the best matches,
and what order the results should be shown in, varies widely from one
engine to another. The methods also change over time as Internet
usage changes and new techniques evolve. There are two main types of
search engine that have evolved: one is a system of predefined and
hierarchically ordered keywords that humans have programmed
extensively. The other is a system that generates an "inverted index "
by analyzing texts it locates. This first form relies much more
heavily on the computer itself to do the bulk of the work.
Most Web search engines are commercial ventures supported by
advertising revenue and thus some of them allow advertisers to have
their listings ranked higher in search results for a fee. Search
engines that do not accept money for their search results make money
by running search related ads alongside the regular search engine
results. The search engines make money every time someone clicks on
one of these ads.
Google is the world's most popular search engine, with a market share
of 80.52 percent as of March, 2017.
The world's most popular search engines (with >1% market share) are:
MARKET SHARE IN MARCH 2017
EAST ASIA AND RUSSIA
In some East Asian countries and Russia,
Google is not the most
popular search engine.
Yandex commands a marketshare of 61.9 percent, compared to
Google's 28.3 percent. In China,
Baidu is the most popular search
engine. South Korea's homegrown search portal,
Naver , is used for 70
percent of online searches in the country.
Yahoo! Japan and Yahoo!
Taiwan are the most popular avenues for internet search in Japan and
Most countries' markets in Western Europe are dominated by Google,
Czech Republic , where
Seznam is a strong competitor.
SEARCH ENGINE BIAS
Although search engines are programmed to rank websites based on some
combination of their popularity and relevancy, empirical studies
indicate various political, economic, and social biases in the
information they provide and the underlying assumptions about the
technology. These biases can be a direct result of economic and
commercial processes (e.g., companies that advertise with a search
engine can become also more popular in its organic search results),
and political processes (e.g., the removal of search results to comply
with local laws). For example,
Google will not surface certain
neo-Nazi websites in France and Germany, where
Holocaust denial is
Biases can also be a result of social processes, as search engine
algorithms are frequently designed to exclude non-normative viewpoints
in favor of more "popular" results. Indexing algorithms of major
search engines skew towards coverage of U.S.-based sites, rather than
websites from non-U.S. countries.
Google Bombing is one example of an attempt to manipulate search
results for political, social or commercial reasons.
Several scholars have studied the cultural changes triggered by
search engines, and the representation of certain controversial
topics in their results, such as terrorism in Ireland and conspiracy
CUSTOMIZED RESULTS AND FILTER BUBBLES
Many search engines such as
Google and Bing provide customized
results based on the user's activity history. This leads to an effect
that has been called a filter bubble . The term describes a phenomenon
in which websites use algorithms to selectively guess what information
a user would like to see, based on information about the user (such as
location, past click behaviour and search history). As a result,
websites tend to show only information that agrees with the user's
past viewpoint, effectively isolating the user in a bubble that tends
to exclude contrary information. Prime examples are Google's
personalized search results and
Facebook 's personalized news stream.
Eli Pariser , who coined the term, users get less
exposure to conflicting viewpoints and are isolated intellectually in
their own informational bubble. Pariser related an example in which
one user searched
Google for "BP" and got investment news about
British Petroleum while another searcher got information about the
Deepwater Horizon oil spill and that the two search results pages were
"strikingly different". The bubble effect may have negative
implications for civic discourse, according to Pariser. Since this
problem has been identified, competing search engines have emerged
that seek to avoid this problem by not tracking or "bubbling" users,
DuckDuckGo . Other scholars do not share Pariser's view,
finding the evidence in support of his thesis unconvincing.
CHRISTIAN, ISLAMIC AND JEWISH SEARCH ENGINES
The global growth of the
Internet and electronic media in the Arab
Muslim World during the last decade has encouraged Islamic
adherents in the
Middle East and Asian sub-continent , to attempt
their own search engines, their own filtered search portals that would
enable users to perform safe searches .
More than usual safe search filters, these Islamic web portals
categorizing websites into being either "halal " or "haram ", based on
modern, expert, interpretation of the "Law of Islam" .
Halal came online in September 2011.
Halalgoogling came online in
July 2013. These use haram filters on the collections from
Bing (and other).
While lack of investment and slow pace in technologies in the Muslim
World has hindered progress and thwarted success of an Islamic search
engine, targeting as the main consumers Islamic adherents, projects
Muxlim , a
Muslim lifestyle site, did receive millions of dollars
from investors like Rite
Internet Ventures, and it also faltered.
Other religion-oriented search engines are Jewgle, the Jewish version
of Google, and SeekFind.org, which is Christian. SeekFind filters
sites that attack or degrade their faith.
SEARCH ENGINE SUBMISSION
Search engine submission is a process in which a webmaster submits a
website directly to a search engine. While search engine submission is
sometimes presented as a way to promote a website, it generally is not
necessary because the major search engines use web crawlers, that will
eventually find most web sites on the
Internet without assistance.
They can either submit one web page at a time, or they can submit the
entire site using a sitemap , but it is normally only necessary to
submit the home page of a web site as search engines are able to crawl
a well designed website. There are two remaining reasons to submit a
web site or web page to a search engine: to add an entirely new web
site without waiting for a search engine to discover it, and to have a
web site's record updated after a substantial redesign.
Some search engine submission software not only submits websites to
multiple search engines, but also add links to websites from their own
pages. This could appear helpful in increasing a website's ranking,
because external links are one of the most important factors
determining a website's ranking. However John Mueller of
stated that this "can lead to a tremendous number of unnatural links
for your site" with a negative impact on site ranking.
Comparison of web search engines
List of search engines
* Use of web search engines in libraries
Web development tools
Search engine manipulation effect
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