Crawling mechanism of Google

Hi friends lets disscuss about google. i know it sounds funny coz everybody know about this famous search engine. It provides an easy interface where you can reach up to your query. It is the most visiting website in year 2011 around the world. But how it works acctually ?

Google's search engine is a powerful tool. Without search engines like Google, it would be quite impossible to find the information you need when you browse the Web. Like all search engines, Google uses a special algorithm to generate search results. While Google shares general facts about its algorithm, the specifics are a company secret. This helps Google remain competitive with other search engines on the Web and reduces the chance of someone finding out how to abuse the system.­Google uses automated programs called spiders or crawlers, just like most search engines.

Google is the famous crawler-based search engine that uses listing mechanism.They "crawl" or "spider" the web, then people search through what they have found.

If you change your web pages, crawler-based search engines eventually find these changes, and that can affect how you are listed. Page titles, body copy and other elements all play a role.
Also like other search engines, Google has a large index of keywords and where those words can be found.

Google uses a trademarked algorithm called PageRank which assigns each Web page a relevancy score.
Web page rank depends on few factors.


1. The frequency and location of keywords within the Web page: If the keyword only appears once within the body of a page, it will receive a low score for that keyword.

2. How long the Web page has existed: People create new Web pages every day, and not all of them stick around for long. Google places more value on pages with an established history.

3. The number of other Web pages that link to the page in question: Google looks at how many
Web pages link to a particular site to determine its relevance.