Search Engines Explained
From its inception the Internet has posed to its users the problem of
how to get the information they need from a large network of interconnected
computers. If you know which particular Web site has your information
and you know its URL (see the definitions section of "What Technologies?"
for a definition of "URL), it is simply a matter of typing it into
the address bar at the top of your Web browser. But much, if not most,
of the time you will be looking for specific information without knowing
which particular Web site has that information. In such cases even a huge
directory listing every Web site that currently exists would be of little
use. So how do you find the Web site you really want on a World Wide Web
that contains millions upon millions of sites?
You use a search engine.
Select a question below to learn more about search engines.
- What is a search engine and how does one work?
- What are some popular search engines?
- Are there any search engines designed for kids?
- Do search engines index the entire Internet?
- What are Boolean operators?
Do search engines index the entire Internet?
No. You might have thought that search engines look all over the Internet
to collect data about your search query. In fact, even the best search
engines can only search certain parts of the Internet. A search engine
spider will, for instance, be stopped dead in its tracks if it encounters
a Web site that requires a user to register and logon to get further information.
For this reason librarians sometimes talk about the "invisible Web"—that
is, the parts of the World Wide Web that are invisible to search engines.
Try visiting InvisibleWeb.com and browse
the links to Web sites that cannot be indexed by traditional search engines.
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