Well, yes and no . (Don't you hate that answer?)
Although using the various search sites works similarly, each has its own unique search methods . But, more important, each has its own unique set of files ”a database ”upon which all searches are based.
You see, no search site actually goes out and searches the entire Web when you ask it to. A search site searches its own index of information about the Web ”its database. The more complete and accurate that database is, the more successful your searches are likely to be.
The database for a search site is created in either (or both) of two ways:
If a search site's database has been created by a crawler, the tool tends to deliver results that are more complete and up-to-date, whereas manually built databases tend to contain more meaningful categorization and more useful descriptive information. Also, most search sites with crawler-built databases do not offer you a way to search by browsing through categories ”a valuable technique you'll pick up later in this chapter. All search sites, however, support the main search method: entering a search term .
How sites are ranked within their categories also varies from search site to search site. Some will simply list sites in alphabetical order. Some sell higher placement for a price, and then list the rest in alphabetical order. Some display results based on the likelihood that the site matches your search term. One site, Google, uses a unique page-ranking system that examines the Internet's elaborate system of links to determine a site's "value" based on the number of other sites that link to it.
Despite differences and strengths and weaknesses among the available tools, the bottom line is this: Any of the major search sites might locate a page or pages that meet your needs, or it might not. If you can't find what you want through one tool, try another. Because each tool has its own database, and each tool applies a different technical method for searching its database, no two search sites turn up exactly the same results for any given topic.