COMMON SEARCH ENGINE PRINCIPLES

To understand SEO, we should have knowledge about ARCHITECTURE of search engines.

Note: As we have various search engines, each search engine have its own principle components.

Here are the main components of Google search engine:

• Spider
• Crawler
• Indexer
• Data Base
• Results Engine
• Web Server

 Spider also known as Search Engine Robots.

• This is a program , it downloads web pages (just like a web browser) .
• The difference is that the browser displays the information presented on each page(text, graphics, etc) while a spider doesn’t.
• A Spider works directly with the underlining HTML code of the page.

 Crawler

• This is a program, finds all the links on each page. Its task is to determine where the Spider should go either by evaluating the links (or) according a pre-defined list of addresses(Home Page, Contact page).
• The Crawler follows these links and tries to find documents not already known to search engines.

In SHORT,

• Crawler finds the links.
• Crawler guides Spider to follow the links.
• Mainly Crawler finds the documents which are New (unknown things).

Note: Crawler reads from left to right, top to bottom.

 Indexer

• This program analysis each page and analysis various elements such as text, headers, structure of stylistic features, special HTML tags (like all HTML tags)etc.

Data Base

• This is a storage area for the data that the search engine downloads and analysis. Sometimes it s called the “Index of the Search Engine”.

 Results Engine

• Results Engines, ranks pages which it determines which pages best match a users query and in what order the pages should be listed. This is done according to the ranking algorithm of search engines.
• It follows the Page Rank, which is a valuable and interesting property and any SEO specialist is most interested in it when trying to improve his site search results.

 Web Server

• The search engine Web Server usually contains a HTML page “with a input field” where the users can specify the search query he/she interested in.
• A Web Server is also responsible in displaying search results to the users in the form of a HTML page.

Note: More page rank indicates trusted and user friendly website.