What Do You About Search Databases?

At the core of a search engine is a database that resembles a huge index. Typically the database contains millions of prices of information about internet sites throughout the world. When you select a hyper link or type in a search string, the search engine consults its index to find all URLs with descriptions that match up to that word. It then provides results of the search within seconds. Search engines differ in their comprehensiveness.
Some such as Alta Vista search deeper than others and will produce matches even to obscure references. This result can be good or bad, depending on how long a list of matches the search returns it can run into the thousands of documents and how much time you want to spend manually looking through the list for something interesting enough to pursue further. Once you find a match, generally you can simply point and click to retrieve the underlying information. Many search engines employ intelligent software called spiders, crawlers, or robots to gather information. These programs visit websites daily to collect vital data, such as URLs descriptive information, and hyper links. Spiders can be tremendously fast, visiting in excess of 1 million sites per day.