If you put quotation marks around any set of words, that tells Google to look for that phrase — those particular words in that exact order. That’s a very powerful capability, made possible by the fact that Google indexes every single word it finds.
Before Google came along, some search engines relied on a knowledge of the syntax of a particular language to try to make less work for the machine and reduce the size of their index. They might throw away the little words, like: a, and, the, or, but… Google doesn’t throw away any words. It keeps all of them and remembers not just what the words are, but also their exact order on the page. In fact, at this level, Google is simply doing a one-to-one match of symbols, without needing to know what those symbols stand for. Hence it can match words and phrases not just in English, but in every language.
Consider the quotation “to be or not to be.” Some search engines consider common little words like those insignificant for search. They focus instead on “keywords” — significant, meaningful English words, and only save those. At Google, there are no “keywords” (except the ones you can use in a search, like “host:”). All words in all languages are important and are saved. You can do a search for the word “to” or the word “be” or the word “not.” You might want to see approximately how many Web pages those words appear on. And if you put words in quotation marks — “to be or not to be” — Google will treat that as a phrase, searching for every instance of all those words together, in exactly that order. That makes it easy to search for any famous quotation. It also means that you can type in a paragraph from an article or a book and search to see if somebody has quoted from or plagiarised that work.
Google gives more weight to uncommon words. So if you type “fish avocado this,” pages that have just “avocado” will appear before pages that have just “fish.” Also, pages that have both words will appear before pages that have only one or the other. And of the pages that have both those words, the pages where “avocado” appears near the beginning or in the title will be at the top of the list. And for purposes of ranking, the word “this” will be ignored, because it appears on so many pages.
You can see how your search terms are treated on the bottom of the results page, under “word count.” There it shows how many pages had each word, and which words were “ignored” for purposes of ranking. But don’t misunderstand “ignored” — those common words are in the index and are very important for doing searches for phrases. And if you definitely want such a word included in the ranking calculations, just put a plus (Main Search only) or AND (Advanced Search only) in front of it.
Words in the Boolean query box are treated as a phrase (as if enclosed in quotation marks) unless they are joined by a Boolean operator. Words in the Sort by box are all treated separately (as if joined by OR), unless they are enclosed by quotation marks, in which case they are treated as a phrase. Boolean operators in the Sort by box are ineffective – that is, treated as ordinary words