People who do not use quotation marks when searching online often receive results that are not related to their query. For example, if someone searches for "Alexander Pope," but does not use quotation marks, he is likely to see results heavily tilted toward the leader of the Catholic Church or even Alexander the Great versus the 18th Century British poet.
The key to using this method is for those searching to use terms that are as specific as possible before enclosing them in quotation marks. It does not help to use quotation marks, for instance, if the phrase is typed incorrectly or if the person searching does not remember the exact line of a given song or movie he is trying to find.
It is important for people to realize, however, that when using quotation marks, a search engine is not capable of returning variants of terms or phrases. This includes plural forms of terms.