Search Engines Search engines are the miracle of the Internet. These sophisticated tools seem to reach right into the global network, and scour its content at your command. In reality, they do not work exactly in this way, although the true nature of search engines is no less fascinating. This is the web page. The index is a database that operates behind the web page.
Some search engines have large indexes, others have small ones.
There are advantages to each. This is what really makes a search engine. Crawlers or spiders are programs that, in a sense, are crawling through the Internet, like spiders crawling across a web. They do this by searching through pages that they do know about looking for new links. When they find one, they follow it, collect the information they need for the index, and then come home to add the new page.