Hello friends, 

What is the main usage of search engine spiders?

A spider is a program that visits Web sites and reads their pages and other information in order to create entries for a search engine index. The major search engines on the Web all have such a program, which is also known as a "crawler" or a "bot."

The SEO Spider is a desktop website crawler and auditor for PC, Mac or Linux which spiders websites' links, images, CSS, script and apps like a search engine to evaluate onsite SEO.

A spider is a software program that travels the Web (hence the name "spider"), locating and indexing websites for search engines. All the major search engines, such as Google and Yahoo!, use spiders to build and update their indexes.

Web spider is a search engine program that is responsible to read through webpage sources and provide information to search engines.

Search engine spiders are used to read the website content & backlinks to increase their search engine visibility.