Search engine
A search engine is a software system that provides hyperlinks to web pages, and other relevant information on the Web in response to a user's query. The user enters a query in a web browser or a mobile app, and the search results are typically presented as a list of hyperlinks accompanied by textual summaries and images. Users also have the option of limiting a search to specific types of results, such as images, videos, or news.
For a search provider, its engine is part of a distributed computing system that can encompass many data centers throughout the world. The speed and accuracy of an engine's response to a query are based on a complex system of indexing that is continuously updated by automated web crawlers. This can include data mining the files and databases stored on web servers, although some content is not accessible to crawlers.
There have been many search engines since the dawn of the Web in the 1990s; however, Google Search became the dominant one in the 2000s and has remained so. As of May 2025, according to StatCounter, Google holds approximately 89–90 % of the worldwide search share, with competitors trailing far behind: Bing, Yandex, Yahoo!, DuckDuckGo, and Baidu. Notably, this marks the first time in over a decade that Google's share has fallen below the 90% threshold. The business of websites improving their visibility in search results, known as marketing and optimization, has thus largely focused on Google.
History
| Year | Engine | Current status |
| 1993 | W3Catalog | |
| 1993 | ALIWEB | |
| 1993 | JumpStation | |
| 1993 | WWW Worm | |
| 1994 | WebCrawler | |
| 1994 | Go.com | , redirects to Disney |
| 1994 | Lycos | |
| 1994 | Infoseek | , redirects to Disney |
| 1995 | Yahoo! Search | , initially a search function for Yahoo! Directory |
| 1995 | Daum | |
| 1995 | Search.ch | |
| 1995 | Magellan | |
| 1995 | Excite | |
| 1995 | MetaCrawler | |
| 1995 | AltaVista | , acquired by Yahoo! in 2003, since 2013 redirects to Yahoo! |
| 1995 | SAPO | |
| 1996 | RankDex | , incorporated into Baidu in 2000 |
| 1996 | Dogpile | |
| 1996 | HotBot | |
| 1996 | Ask Jeeves | |
| 1997 | AOL NetFind | |
| 1997 | goo.ne.jp | |
| 1997 | Northern Light | |
| 1997 | Yandex | |
| 1998 | ||
| 1998 | Ixquick | as Startpage.com |
| 1998 | MSN Search | as Bing |
| 1998 | empas | |
| 1999 | AlltheWeb | |
| 1999 | GenieKnows | , rebranded Yellowee |
| 1999 | Naver | |
| 1999 | Teoma | |
| 2000 | Baidu | |
| 2000 | Exalead | |
| 2000 | Gigablast | |
| 2001 | Kartoo | |
| 2003 | Info.com | |
| 2004 | A9.com | |
| 2004 | Clusty | , Yippy, previously Clusty, now owns Togoda.com |
| 2004 | Mojeek | |
| 2004 | Sogou | |
| 2005 | SearchMe | |
| 2005 | KidzSearch | , Google Search |
| 2006 | Soso | , merged with Sogou |
| 2006 | Quaero | |
| 2006 | Search.com | |
| 2006 | ChaCha | |
| 2006 | Ask.com | |
| 2006 | Live Search | as Bing, rebranded MSN Search |
| 2007 | wikiseek | |
| 2007 | Sproose | |
| 2007 | Wikia Search | |
| 2007 | Blackle.com | , Google Search |
| 2008 | Powerset | |
| 2008 | Picollator | |
| 2008 | Viewzi | |
| 2008 | Boogami | |
| 2008 | LeapFish | |
| 2008 | Forestle | |
| 2008 | DuckDuckGo | |
| 2008 | TinEye | |
| 2009 | Bing | , rebranded Live Search |
| 2009 | Yebol | |
| 2009 | Scout | |
| 2009 | NATE | |
| 2009 | Ecosia | |
| 2009 | Startpage.com | , sister engine of Ixquick |
| 2010 | Blekko | , sold to IBM |
| 2010 | Cuil | |
| 2010 | Yandex | |
| 2010 | Parsijoo | |
| 2011 | YaCy | , P2P |
| 2012 | Volunia | |
| 2013 | Qwant | |
| 2014 | Egerin | , Kurdish / Sorani |
| 2014 | Swisscows | |
| 2014 | Searx | |
| 2015 | Yooz | |
| 2015 | Cliqz | |
| 2016 | Kiddle | , Google Search |
| 2017 | Presearch | |
| 2018 | Kagi | |
| 2020 | Petal | |
| 2021 | Brave Search | |
| 2021 | You.com | |
| 2022 | Perplexity |
Pre-1990s
In 1945, Vannevar Bush described an information retrieval system that would allow a user to access a great expanse of information, all at a single desk, which he called a memex. He described this system in an article titled "As We May Think" in The Atlantic Monthly. The memex was intended to give a user the capability to overcome the ever-increasing difficulty of locating information in ever-growing centralized indices of scientific work. Vannevar Bush envisioned libraries of research with connected annotations, which are similar to modern hyperlinks.Link analysis eventually became a crucial component of search engines through algorithms such as Hyper Search and PageRank.
1990s: Birth of search engines
The first internet search engines predate the debut of the Web in December 1990: WHOIS 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 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 on the Internet was Archie. The name stands for "archive" without the "v". It was created by Alan Emtage, computer science student at McGill University in Montreal, Quebec, Canada. The program downloaded the directory listings of all the files located on public anonymous FTP 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 led to two new search programs, Veronica and Jughead. Like Archie, they searched the file names and titles stored in Gopher index systems. Veronica provided a keyword search of most Gopher menu titles in the entire Gopher listings. Jughead 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 catalogs were maintained by hand. Oscar Nierstrasz at the University of Geneva wrote a series of Perl scripts 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 Perl-based 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 November 1993. 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.
JumpStation 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 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 web page, which has become the standard for all major search engines since. It was also the search engine that was widely known by the public. Also, in 1994, Lycos was launched and became a major commercial endeavor.
The first popular search engine on the Web was Yahoo! Search. The first product from Yahoo!, founded by Jerry Yang and David Filo in January 1994, was a Web directory called Yahoo! Directory. In 1995, a search function was added, allowing users to search Yahoo! Directory. It became one of 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.
Soon after, a number of search engines appeared and vied for popularity. These included Magellan, Excite, Infoseek, Inktomi, Northern Light, and AltaVista. Information seekers could also browse the directory instead of doing a keyword-based search.
In 1996, Robin Li developed the RankDex site-scoring algorithm for search engines results page ranking and received a US patent for the technology. It was the first search engine that used hyperlinks to measure the quality of websites it was indexing, predating the very similar algorithm patent filed by Google two years later in 1998. Larry Page referenced Li's work in some of his U.S. patents for PageRank. Li later used his RankDex technology for the Baidu search engine, which was founded by him in China and launched in 2000.
In 1996, 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 search engine 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 March 2000.