Search engines are large collections (searchable databases) of links to resources on the Internet. Enter keywords and the search engine will return a list of Web pages it has
indexed from the Internet that contain those terms.
There are many search engines available on the Web. Search Engine Watch maintains a comprehensive list of Web search engines and their features
The number of sources it searches, and
The type of resources it searches
Often, this information is provided on the search engine's home page. Here are examples of 2 popular search engines.
Google's index to Web resources is comprised of more than 1 billion Web pages.
The Web database contains over 54 million Web pages. The Usenet database contains an archive of more than 4 million recent Usenet articles.