Why are the services below considered to be the major search engines? They are all either well-known or well-used.

For webmasters, these services are the most important places to be listed, because they can potentially generate so much traffic.

For searchers, these well-known, commercially-backed search engines generally mean more dependable results. These search engines are more likely to be well-maintained and upgraded when necessary, to keep pace with the growing web.

Not all of the services below are "true" search engines that crawl the web. For instance, Yahoo and the Open Directory both are "directories" that depend on humans to compile their listings. In fact, most of the services below offer both search engine and directory information, though they will predominately feature one type of results over the other.

AllTheWeb.com (FAST Search)
http://www.alltheweb.com
AllTheWeb.com (also known as FAST Search) consistently has one of the largest indexes of the web. FAST also offers large multimedia and mobile/wireless web indexes, available from its site. The site, also known as AllTheWeb.com, is a showcase for FAST's search technologies. FAST's results are provided to numerous portals, including those run by Terra Lycos. FAST Search launched in May 1999.

AltaVista
http://www.altavista.com
AltaVista is one of the oldest crawler-based search engines on the web. It has a large index of web pages and a wide range of power searching commands. It also offers news search, shopping search and multimedia search. AltaVista opened in December 1995. It was owned by Digital, then run by Compaq (which purchased Digital in 1998), then spun off into a separate company which is now controlled byCMGI.

AOL Search
http://search.aol.com/
AOL Search allows its members to search across the web and AOL's own content from one place. The "external" version, listed above, does not list AOL content. The main listings for categories and web sites come from the Open Directory (see below). Inktomi (see below) also provides crawler-based results, as backup to the directory information.

Ask Jeeves
http://www.askjeeves.com
Ask Jeeves is a human-powered search service that aims to direct you to the exact page that answers your question.

Direct Hit
http://www.directhit.com
Direct Hit measures what people click on in the search results presented at its own site and at its partner sites, such as HotBot. Sites that get clicked on more than others rise higher in Direct Hit's rankings. Thus, the service dubs itself a "popularity engine." Aside from running its own web site, Direct Hit provides the main results which appear at HotBot (see below) and is available as an option to searchers at MSN Search. Direct Hit is owned by Ask Jeeves (above). Some Direct Hit information appears at Ask Jeeves

Google
http://www.google.com
Google is a top choice for web searchers. It offers the largest collection of web pages of any crawler-based search engine. Google makes heavy use of link analysis as a primary way to rank these pages. 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. The system works so well that Google has gained wide-spread praise for its high relevancy. Google provides web page search results to a variety of partners, including Yahoo and Netscape Search (see below). Google also provides the ability to search for images, through Usenet discussions and its own version of the Open Directory (see below).

HotBot
http://www.hotbot.com
In most cases, HotBot's first page of results comes from the Direct Hit service (see above), and then secondary results come from the Inktomi search engine, which is also used by other services. It gets its directory information from the Open Directory project (see below). HotBot launched in May 1996 as Wired Digital's entry into the search engine market. Lycos purchased Wired Digital in October 1998 and continues to run HotBot as a separate search service.

iWon
http://www.iwon.com
iWon's results come from both Overture & Inktomi. iWon gives away daily, weekly and monthly prizes in a marketing model unique among the major services. It launched in Fall 1999.

Inktomi
http://www.inktomi.com
Originally, there was an Inktomi search engine at UC Berkeley. The creators then formed their own company with the same name and created a new Inktomi index, which was first used to power HotBot. Now the Inktomi index also powers several other services. All of them tap into the same index, though results may be slightly different. This is because Inktomi provides ways for its partners to use a common index yet distinguish themselves. There is no way to query the Inktomi index directly, as it is only made available through Inktomi's partners with whatever filters and ranking tweaks they may apply.

LookSmart
http://www.looksmart.com
LookSmart is a human-compiled directory of web sites. In addition to being a stand-alone service, LookSmart provides directory results to MSN Search, Excite and many other partners. Inktomi provides LookSmart with search results when a search fails to find a match from among LookSmart's reviews. LookSmart launched independently in October 1996, was backed by Reader's Digest for about a year, and then company executives bought back control of the service.

Lycos
http://www.lycos.com
Lycos started out as a search engine, depending on listings that came from spidering the web. In April 1999, it shifted to a directory model similar to Yahoo. Its main listings come from AllTheWeb.com with some results from the Open Directory project. In October 1998, Lycos acquired the competing HotBot search service, which continues to be run separately.

MSN Search
http://search.msn.com
Microsoft's MSN Search service is a LookSmart-powered directory of web sites, with secondary results that come from Inktomi. Direct Hit data is also made available.

Netscape Search
http://search.netscape.com
Netscape Search's results come primarily from the Open Directory and Netscape's own "Smart Browsing" database, which does an excellent job of listing "official" web sites. Secondary results come from Google. At the Netscape Netcenter portal site, other search engines are also featured.

Open Directory
http://dmoz.org/
The Open Directory uses volunteer editors to catalog the web. Formerly known as NewHoo, it was launched in June 1998. 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. Netscape-owner AOL also uses Open Directory information, as does Google and Lycos.

Yahoo
http://www.yahoo.com
Yahoo is the web's most popular search service and has a well-deserved reputation for helping people find information easily. The secret to Yahoo's success is human beings. It is the largest human-compiled guide to the web, employing about 150 editors in an effort to categorize the web. Yahoo has well over 1 million sites listed. Yahoo also supplements its results with those from Google. If a search fails to find a match within Yahoo's own listings, then matches from Google are displayed. Google matches also appear after all Yahoo matches have first been shown. Yahoo is the oldest major web site directory, having launched in late 1994.