SUBTRACTING SITES USING "NOT"

Sometimes you  know that typing in one keyword only will bring up a long list of web sites, and many of them will be on topics that don't have anything to do with the topic you're really researching. For example, if you're doing research on dolphins, you will find information on dolphins, as well as the Miami Dolphins, who are not really dolphins, but football players!

Fortunately there is a way to tell the search engine not to include information on the Miami Dolphins, i.e. by including the word "not" between the keywords. Look at this example:

This can be illustrated a diagram of two sets showing the sites that will be listed if you type in one keyword, and exclude another:

The circle on the left represents all the web sites that the search engine could find containing the word "dolphins". The circle on the right represents all the web sites that the search engine could find containing the word "football". The colored area represents all the web sites that contain web sites on dolphins, except those that refer to football teams named after dolphins, which would include the Miami Dolphins.