www.Google.com
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.

Excite
Excite is one of the most popular search services on the web. It offers a medium-sized 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.

Yahoo
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 (Google took over from Inktomi in July 2000). 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.

Alta Vista
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 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.

FAST Search
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.

Ask Jeeves
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. Results from Ask Jeeves also appear within AltaVista.

AOl Search
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. Inktomi also provides crawler-based results, as backup to the directory information. Before the launch of AOL Search in October 1999, the AOL search service was Excite-powered AOL NetFind.

Lycos
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 spidering the web. Lycos also feature another directory of web sites called Lycos Community Guides. Sites are automatically listed in these guides using technology from WiseWire, a company Lycos acquired in early 1998. Lycos is one of the oldest search services, around since May 1994. It began as a project at Carnegie Mellon University. The name Lycos comes from the Latin for "wolf spider." In October 1998, Lycos acquired the competing HotBot search service, which continues to run separately.

Direct Hit
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).

Go/Infoseek
Go is a portal site produced by Infoseek and Disney. It offers portal features such as personalization and free e-mail, plus the search capabilities of the former Infoseek search service, which has now been folded into Go. Searchers will find that Go consistently provides quality results in response to many general and broad searches, thanks to its ESP search algorithm. It also has an impressive human-compiled directory of web sites. Go was officially launched in January 1999. It is not related to GoTo, below. The former Infoseek service launched in early 1995.

GoTo.com
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 was launched in 1997 and it 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).

HotBot
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 (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 was 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.

Go2net.com
One of the oldest meta search services, MetaCrawler began in July 1995 at the University of Washington. MetaCrawler was purchased by go2net, an online content provider, in Feb. 97. The commercial backing has helped improve the responsiveness of the service. MetaCrawler now powers searches at the Go2Net portal site.

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 was launched in the fall of 1999.

Microsoft Network (MSN)
Microsoft's MSN Search service is a LookSmart-powered directory of web sites, with secondary results that come from AltaVista. RealNames and Direct Hit data is also made available. MSN Search also offers a unique way for Internet Explorer 5 users to save past searches.

NBCi ( Formerly Snap )
NBC Internet (Formerly Snap) is a human-compiled directory of web sites, supplemented by search results from Inktomi. Like LookSmart, it aims to challenge Yahoo as the champion of categorizing the web. Snap was launched in late 1997 and is backed by Cnet and NBC.

Netscape's Netcenter
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
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, while AltaVista and HotBot prominently feature Open Directory categories within their results pages.

WebCrawler
WebCrawler has the smallest index of any major search engine on the web -- think of it as Excite Lite. The small index means WebCrawler is not the place to go when seeking obscure or unusual material. However, some people may feel that by having indexed fewer pages, WebCrawler provides less overwhelming results in response to general searches. WebCrawler opened to the public on April 20, 1994. It was started as a research project at the University of Washington. America Online purchased it in March 1995 and was the online service's preferred search engine until Nov. 1996. That was when Excite, a WebCrawler competitor, acquired the service. Excite continues to run WebCrawler as an independent search engine.

LookSmart
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.

Reciprocal Links Reciprocal links are nothing but a text/ banner link to a site that, somewhere in its pages, carries a similar text/banner link to your own site. Reciprocal Links are another method of attracting traffic. Post your favourite link exchanges and discuss the issues relating to this style of online community.

What is Link Popularity? Link popularity is the number of links that point to a webpage. Link Popularity is a crucial factor, used by almost all of the search engines to rank websites. Reciprocal links form a vital part of any website promotion effort.

Search engines don't just look at the content of a webpage to determine if it is a good match for a search. Thousands and thousands of webpages contain the same keywords (in different combinations) so matching a search term with a page's content is not enough to build an ordered list of results to a search query.

Search engines also count the number of other webpages that "validate", by linking, that a particular webpage is a good match for a search on certain keywords (link popularity). The text contained in the link that point to a webpage is considered as well. If the text in the link that points to a webpage contains the queried keywords, the search engine considers that webpage a better match to the search query on those keywords.

Reciprocal links equals free advertising. The quality and quantity of reciprocal links with other web sites allows you to increase your link popularity. It is not only the number of the links (link popularity) that counts, but also the "quality" of the links. A link from a good-quality webpage (ranked high by the search engines) matters more than many links from low-ranked webpages.

One of the first search engines that used link popularity as a key factor in ranking websites was Google. One can check the number of links pointing to a website (link popularity) by querying Google with the search keywords "link:http://whateversite.com" (without the red quotes). Most search engines have similar functions for link popularity check.

There are also many free services that allow one to query several search engines at a time regarding the link popularity of a website.

Since link popularity has become such an important factor in determining search engine positioning, many solutions have been proposed for improving link popularity. A very popular and inexpensive way is Reciprocal Links(links swap). Done properly, it can dramatically improve your link popularity!