A search engine contains a database of domain names or "Web address." This database is usually built by Webcrawlers, spiders, or robots. These are programs that search the World Wide Web for new Web sites and Web pages. The new Web pages are cataloged into the search engine's database.

A search engine can provide a wealth of information on any topic. You can use it to find a good restaurant in a distant city, or to perform research for that report that is due in the morning. You can also use it to find long lost friends, and phone numbers.