“Internet search engines are special sites on the Web that are designed to help people find information stored on other sites. There are differences in the ways various search engines work, but they all perform three basic tasks:
Early search engines held an index of a few hundred thousand pages and documents, and received maybe one or two thousand inquiries each day. Today, a top search engine will index hundreds of millions of pages, and respond to tens of millions of queries per day.” ~ How Stuff Works
Today Google is the predominant search engine, but did you know that not all search engines work the same way? Do the same search in each of these various engines and you will be amazed at how different the results can be.