O.K., so we all know that there are literally billions of Web pages out there right. The question is, how do we find what were looking for with all those pages out there? Well, the key to finding information or at least the right direction to head is in learning how search engines and directories work. In this article we will examine just how they work.
What are Search Engines/Directories Anyway?
You may know that search engines and directories are tools that have been developed to help users navigate through much of the information that is out there on the Information Superhighway. But you may not know how they actually work. The following is a brief outline of what goes on behind the scenes.
Search Engines are hard working software programs that explore the Internet and build indexes of available pages. These pages are then made available to users. By using these search tools you can quickly find those resources or products that are relevant to you. Search Engines get their name from the software that searches through the indexed databases it creates. These indexes are special Web documents which can be searched rather than read. The results of such a search are displayed in another Web document containing links to the documents found.
How Do Search Engines Work?
Search engines consist of three parts: A Spider, the Index, and the Search Software.
The Spider: The Spider, also called "the crawler", visits Web pages to build an indexed database for the search engine. Most engines run several spiders that explore the Web as a team. The crawler looks for new Web pages or changes in existing ones to place in it's catalog. The number of Web pages visited and how often varies from engine to engine, but the typical crawler visits several million Web pages a week.
The Index: The Index part, also called "the catalog", is where the spider stores what it finds. Most engines contain only a text copy of every Web page visited, and removes often repeated words such as "the" or "an" to save space.
The Search Software: The Search part of the engine is software that allows you to look for pages containing information in response to one or more key search words that you have entered related to what you are looking for. It then displays the results, called "queries," ranked by a method that usually involves the location and frequency of the matching search words within the Web pages themselves.
Any given search usually results in several hundred to several hundred-thousand possible relevant Web homepage that matches your search inquiry. If this sounds complicated it's really not. A search engine will list the top ten to twenty Web sites out of the results for you with direct links to those pages.
Search directories on the other hand are different from search engines. A search engine finds Web sites on their own, automatically, but a search directory depends on people who operate the site to submit Web sites manually. But that's not all, other people are then required to classify them, and then, you get to select from the listing. The only downfall for directories is that search engines find Web sites automatically that directories might not know about. Directories may also suffer from outdated or broken links, but usually more often turn up excellent and relevant helpful search results.
Yahoo! is an example of an excellent search directory. Most people think that it is a search engine because it's a major guide to the Web. In reality, Yahoo is a directory that contains more than a million listings, categorized far more efficiently than a search engine could ever do.