This operator requests that multiple words and phrases all be present in your query results and displays these results at the top of the list of results. However, most search engines and directories interpret this operator in a way that does not prohibit results that do not include all the words or phrases. Searching for education AND computer will return documents that contain both the word "computer" and the word "education" in them as the top results.

Understanding how a search engine works helps you to understand how your pages are ranked in the search engine, but how your pages are found is another story entirely. That is where the human element comes in. Search means different things to different people. For example, one of my colleagues searches the Internet using the same words and phrases he would use to tell someone about a topic or even the exact question that he’s trying to get answered. It’s called natural language. Another, however, was trained in search using Boolean search techniques. She uses a very different syntax when she is creating a search term. Each of them returns different search results, even when each is using the same search engines.
The characteristics of search refer to how users search the Internet. This can be everything from the heuristics they use when creating a search term to the selection the user makes once the search results are returned. One interesting fact is that more than half of American adults search the Internet every time they go online. And in fact, more people search the Internet than use the yellow pages when they’re looking for phone numbers or the locations of local businesses.
This wealth of search engine users is fertile ground for SEO targeting. And the better you understand how and why users use search engines, and exactly how search engines work, the easier it will be to achieve the SEO you’re pursuing.

Boolean searches allow you to combine words and phrases using the words

1. AND,
2. OR,
3. NOT and
4. NEAR

(otherwise known as Boolean operators) to limit, widen, or define your search. Most Internet search engines and Web directories default to these Boolean search parameters anyway, but a good Web searcher should know how to use basic Boolean operators.