There are several search engines and directories you can use on the internet. What you might not realize is that they do have different information. Some search engines are updated more frequently. Some utilize results from the other search engines. Also they all use slightly different approaches to capturing information.
If you are researching something on the internet, it is a good idea to check a few different search engines. Some results will be duplicated, but often you will find sites that are not listed at all in the search engine that you started with.
I usually start with Google. But I often also check Yahoo and then AltaVista. There are dozens of search engines available. Find the ones you like and save them on your Favorites list.