Sponsor Links
Contact us for sponsor link $10.00 per month.
Active Links: 13266
Pending Links: 52
Todays Links: 4
Total Articles: 242
Total Categories: 13
Sub Categories: 451
About Us
| Articles
| How Does a Search Engine Operate? | | Date Added: March 16, 2010 02:58:39 PM |
| An Internet search engine is a software programme specially-designed to search for data on the Web. The search results are usually presented in the form of a list and are normally called hits. The data may comprise web pages, images, information and other types of files. Some search engines also gather data available in databanks or open directories. Unlike Web directories that are maintained by human editors, search engines work automatically or are a mix of algorithmic and human input.
Web search engines operate by storing data about countless web pages which they retrieve from the WWW. These pages are retrieved by a web crawler, also known as a spider. It is an automated Web browser that follows every link it sees. The content of each page is then analyzed to determine how it should be indexed. Words, for example, are extracted from titles, headings or special fields called meta tags. Data about web pages are stored in an index databank for further use in queries. Some search tools, such as Google, save and store the entire or part of the source page (differently called a cache) and information about web pages, whereas others, such as AltaVista, store every word of every page they discover. The cached page always contains the initial search text, because it is the one that was actually indexed. Hence, it can be very useful because it includes information that may no longer be available elsewhere.
Once a user has typed search words in the search field, the tool carries out checks on its index and displays a list of the most suitable web pages according to its parameters, usually with a short summary containing the document's title and at times excerpts from the text. Some search engines have installed an advanced option called proximity search which allows users to determine the length between search words.
The usefulness of a search engine hinges on the relevancy of the result set it gives back. Since there may be millions of web pages containing a certain key word or word combination, web pages can be grouped into relevant and irrelevant ones. The results can be ranked to show the "best" ones first.
How a search engine determines which pages are the best matches, and in what arrangement the results should be shown, is specific to a search engine. The techniques also alter with time, since the use of the Internet undergoes alterations and new techniques are developed. |
|
