What is Spider?

Posted: July 30, 2014 in SEO
Tags: ,

A program Google Crawlersthat automatically fetches Web pages. Spiders are used to feed pages to search engines. It’s called a spider because it crawls over the Web. Another term for these programs is webcrawler. Because most Web pages contain links to other pages, a spider can start almost anywhere. As soon as it sees a link to another page, it goes off and fetches it. Large search engines , like Alta Vista, have many spiders working in parallel.

 

 

Importance of spiders:-

If a search engine spider can not access your pages because of poor site structure and navigation, they can not index your pages. If your pages don’t get indexed, they are not going to have a chance at high search engine rankings. By following a few helpful hints, you will be able to provide many access points to your important pages so that a search engine spider will be able to find them and index them.

How Web Search Engines Work:-

Crawler-based search engines are those that use automated software agents (called crawlers) that visit a Web site, read the information on the actual site, read the site’s meta tags and also follow the links that the site connects to performing indexing on all linked Web sites as well. The crawler returns all that information back to a central depository, where the data is indexed. The crawler will periodically return to the sites to check for any information that has changed. The frequency with which this happens is determined by the administrators of the search engine.

Human-powered search engines rely on humans to submit information that is subsequently indexed and catalogued. Only information that is submitted is put into the index. In both cases, when you query a search engine to locate information, you’re actually searching through the index that the search engine has created —you are not actually searching the Web. These indices are giant databases of information that is collected and stored and subsequently searched. This explains why sometimes a search on a commercial search engine, such as Yahoo! or Google, will return results that are, in fact, dead links. Since the search results are based on the index, if the index hasn’t been updated since a Web page became invalid the search engine treats the page as still an active link even though it no longer is. It will remain that way until the index is updated.

Major search engines:-
Google
YahooSEO Sharing
MSN/Bing

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s