Rafael Souza (CISOof hackers online club) introduces the fundamentals of Google Hacking. The information available on the companys web servers are likely to be in the databases of Google. A misconfigured server may expose several business information on Google. It is difficult to get access to files from database sites through Google, but it is possible that even having been altered or removed, can still access it using the Google cache feature. The allintext operator is perhaps the simplest to use as it performs the function of most known search engines like : locate the term in the page text.”]
Source: http://securityaffairs.co/wordpress/20169/hacking/google-hacking-2.html