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). Google (see below) also provides crawler-based results, as backup to the directory information.

AltaVista is consistently one of the largest search engines on the web, in terms of pages indexed. Its comprehensive coverage and wide range of power searching commands makes it a particular favorite among researchers. It also offers a number of features designed to appeal to basic users, such as "Ask AltaVista" results, which come from Ask Jeeves (see below), and directory listings from the Open Directory and LookSmart. 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 by CMGI.

Ask Jeeves is a human-powered search service that aims 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 matching web pages from various search engines. The service went into beta in mid-April 1997 and opened fully on June 1, 1997. Some results from Ask Jeeves also appear within AltaVista.

Excite is one of the more popular search services on the web. It offers a fairly large index and integrates non-web material such as company information and sports scores into its results, when appropriate. Excite was launched in late 1995. It grew quickly in prominence and consumed two of its competitors, Magellan in July 1996, and WebCrawler in November 1996. These continue to run as separate services.

Formerly called All The Web, FAST Search aims to index the entire web. It was the first search engine to break the 200 million web page index milestone and consistently has one of the largest indexes of the web. The Norwegian company behind FAST Search also powers some of the results that appear at Lycos (see below). FAST Search launched in May 1999.

Google is a search engine that 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. The system works so well that Google has gained wide-spread praise for its high relevancy. Google also has a huge index of the web and provides some results to Yahoo and Netscape Search.

Overture Unlike the other major search engines, GoTo sells its main listings. Companies can pay money to be placed higher in the search results, which GoTo feels improves relevancy. Non-paid results come from Inktomi. GoTo launched in 1997 and incorporated the former University of Colorado-based World Wide Web Worm. In February 1998, it shifted to its current pay-for-placement model and soon after replaced the WWW Worm with Inktomi for its non-paid listings. GoTo is not related to Go (Infoseek). Paid listing from GoTo also appear on other major search engines, including AltaVista, AOL Search, Lycos, HotBot, Direct Hit, MSN, Yahoo,Excite and Netscape Search.

HotBot is a favorite among researchers due to its many power searching features. In most cases, HotBot's first page of results comes from the Direct Hit service, 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 . 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 Backed by US television network CBS, iWon has a directory of web sites generated automatically by Inktomi, which also provides its more traditional crawler-based results. iWon gives away daily, weekly and monthly prizes in a marketing model unique among the major services. It launched in Fall 1999.

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 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 the Open Directory project, and then secondary results come from the FAST Search engine. Some Direct Hit results are also used. In October 1998, Lycos acquired the competing HotBot search service, which continues to be run separately.

Microsoft's MSN Search service is a powered by Microsft MSN Search also offers a unique way for Internet Explorer users to save past searches.

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.

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. Lycos and AOL Search also make heavy use of Open Directory data.

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 over 1 million sites listed. Yahoo also supplements its results with those from Google (beginning in July 2000, when Google takes over from Inktomi). If a search fails to find a match within Yahoo's own listings, then matches from Google are displayed. Today Yahoo search results coming 100% from the Yahoo Network. Yahoo is the oldest major web site directory, having launched in late 1994