What is the main idea of the following paragraph? A spider, also known as a robot or a crawler, is actually just a program that follows, or "crawls," links throughout the Internet, grabbing content from sites and adding it to a database. Spiders only can follow links from one page to another and from one site to another. That is the primary reason why links to your site (inbound links) are so important. Links to your Web site from other Web sites will give the search-engine spiders more information. The more times they find links to your site, the more times they will stop by and visit. Search engines rely on spiders to create their vast knowledge of Web sites.

A spider crawls throughout the Internet.
A spider crawls throughout the Internet.

A crawler is the same thing as a robot.
A crawler is the same thing as a robot.

Links of your Web site going to other Web sites are important.
Links of your Web site going to other Web sites are important.

A spider is software that follows links from site to site, acquiring content and information.
A spider is software that follows links from site to site, acquiring content and information.