How Search Engines Works

Suppose you want to buy somthing online or you need to get some information from internet related any topic you want, then what will you do ? You will deffinetily go to search engine and try to find related information.

Now think you got all information from world wide web through the search engine but did you think how search enginge put all desired search in front of your eyes. read the following article to know this.

Search engines consist of five discrete software components:


Spider : A search engine program that downloads webpages.
Spider, also called a robot or a crawler, is actually the only program that will follow, or "crawls", links to the Internet, grabbing the content of sites, and adding it to the search engine indexes.

The spiders can follow links from one page to another and from one place to another. This is the main reason why links to your site (inbound links) is so important. Links to your site from other Web sites provide search engines more "food" to chew. The more times they find links to your site, the more times they'll stop and visit. Google is based in particular on its spiders index their lists to create enormous.

Spiders find Web pages by following links to other Web pages, but you can also send web pages directly from a search engine or directory, and ask them to visit the spider. In fact, it's a good idea to send manually edited directories like Yahoo, and usually spiders from other search engines (like Google) to find and add it to the database. It may be useful to submit your URL directly to the different search engines, as well, but Spider-based engines usually pick up on the site, regardless of whether you have sent the search engine.

Crawler : A wandering spider that automatically follows links found on pages.
Component of search engine that gather listings by automatically “crawling” the web. A search engine’s crawler (also called a spider or robot), follows links to web pages. It makes copies of the web pages found and stores these in the search engine’s index.

Indexer : A blender like program that dissects webpages that are downloaded by spiders.
An indexer rips apart a page into it's various components and analyze them. Entities such as, titles, headings, links, text, constructs, bold, italic, and other style portions of a page are ripped apart and analyzed.

The database : A warehouse of the pages downloaded and processed.
The database is the storage medium for all the data a search engine downloads and analyzes. This can require huge amounts of storage space.

Search engine results engine : Digs search results out of the database.

Ah, the heart of the beast. It is the results engine's job to decide what pages matches a users search. This is the portion of a search engine you interact with when you perform a search. It is also the one part we are concerned with here.

When a user types in a keyword and does a search, the search engine decides what to match for results under varying criteria. The means with which it decides is called an algorithm. You may hear search engine optimization (SEO) professionals discuss "algos" from time to time and this is what they are referring too.