No one has everything!

Much of the content of the Web is not found by search engine sites. This content is referred to as the "invisible" or "deep" web.

Even the 30% or less of the Web actually covered by search engines is not found by any single search engine. When doing serious research, consulting more than one search engine is recommended because the results returned from each search engine site will be quite different. Each may have as much as 40% unique content.

Click on this link to the Search Engine Watch and read the graphs. This will give you a good, quick overview of search engines. For a description of major search engines, click here.

Many people think that Yahoo is the biggest search engine because of its popularity. It's actually a directory.

Chart from July 2006.

Remember, you will probably not be able to rely on one search tool for all your needs. Try out different search engine sites and become familiar with how they work. Do the exact same search in several and notice the top 10 results in each. This exercise alone will provide you with a wealth of information. More about the basics of search engines and directories here.