Search Engine Structure

Search Engine Structure:
from WebHostPad.com

There are three major components to every search engine; a spider, an index, and search engine software.

A "software spider" is an unmanned program operated by a search engine that surfs the Web just like you or I would. As the spider visits each website, it records (saves to its database) all the words on each site and notes each link to other sites. It then "clicks" on a link, and off it goes to read, index, and store another website.

All the data recorded by the spider is saved into the index, a database of all Web pages reviewed by the spider. When Web pages are altered, the spider will review and updated the index with the newest information. It can take six to eight weeks for new Web pages to be added to the index even after the spider has reviewed and recorder there information because of the extreme number of pages in the index.

Search engine software is used to provide search results to search engine users. The software runs through all of the pages recorded in the index to find the most relevant matches to a search, ranking these matches in order of relevancy. Each search engine has different rules of how to determine relevancy, but all search engines follow more or less the same basic guidelines.

When a search is preformed, the results are ranked by the number of times your search term occurs on a particular page. The software is looking for:

Whether that term appears on the page title (URL)
How close to the top of the page the keyword appears in the text
Whether the keyword is within the website meta tags
The frequency of use of the keyword
The link popularity on the site
Consistency of the information on the entire website.

Not all search engines use all the above criteria, but that is basically what they are looking at when indexing a site.

So we have search engines that are both powerful and widely accepted, but they're structured in such a way that listings are not automatic. Not only that, it's impossible to index all the pages anyway. This is why search engines are constantly changing and up grading to new advanced software.

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