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Author: seomul | Total views: 60 Comments: 0
Word Count: 657 Date: Tue, 3 Mar 2009 2:05 AM

How Search Engines And Directories Work

Anyone who accesses the Internet in search of information will inevitably head straight for a search engine or a directory. Most people hold the impression that they are one and the same, but there are some fundamental differences between search engines and directories. This article will explore in detail the differences between search engines and directories.

About Internet Search Engines

A web search engine is essentially a website that allows you to input a word or phrase related to whatever you are searching for. A series of relevant results will then be produced, containing links to websites that might contain what you are looking for. Some of the popular search engines include Google, Yahoo and Nexplore. The main page of most popular search engines is exceedingly simple, containing a single entry field where you can input your query, then click a search button, whereupon most major search engines will search its database for sites matching your entry.

A results page will appear with the top 10 website results for your query, with options to link to the following pages of results as well. Web search engines make use of various factors when ranking sites, such as the number of times a relevant word or phrase is used in the text on the site, how many other sites are linked to it, the number of times keywords can be found in the site's code, many others. Most of the top search engines operate in much the same way as each other, although they may use slightly different criteria in ranking websites.

True search engines work by first using a program known as a crawler or spider. This program trawls the Internet, following links and indexing the websites they find in a database. Once a spider program has indexed a website, the search engine will revisit the site regularly in order to keep its records updated. Some search engines may even use spider programs multiple times each day, especially if they think the websites indexed by the engine need to be updated.

You will find that there are many search engines available that specialize in searching for other file types or information types. Some items search engines may specialize in indexing are images, files, music, and many more. Some search engines are also particularly useful for finding specific types of sites such as shopping sites.

About Internet Directories

Directories function very differently from search engines. Directories do not make use of spider or crawler programs. Instead, directories are usually manually maintained by humans. A directory will usually have an editor who vets submissions to the directory or else it will have someone who actively searches the Internet for sites to add to their listings. Directories may vary in size from the small to the truly massive. An excellent example of a large directory is Dmoz. It is a not-for-profit directory edited completely by volunteers. The Internet also contains countless smaller directories that specialize in a particular niche. No matter what you are looking for on the web, you are bound to find a directory that caters to it.

Comparing Search Engines And Directories

A directory edited by someone will usually contain listings of sites of higher quality since, unlike a search engine; sites added to a directory must undergo a manual inspection and approval process. A directory also separates its listings according to categories - something search engines do not do. A search engine will contain a great deal more links than a directory, however, and the results you find on a search engine are also likely to be fresher.

Whether you decide to make use of a search engine or a directory really depends on what it is you are searching for and which of them is able to offer you better results to suit your needs.