Google is one of the best Search Engine . Not only that but also Google is very good friend of hackers. If you are very new to hacking then you may not know this but actually Most of public/private information we can gather using the Google, Even it is possible hack a server,website,random site using the Google.
Perhaps Somewhere i already explained about Public information Gathering. Anyway, If you want be more expert, want know more about Google hacking, Want to learn the technique just Go here:
Lots of dorks you will find in exploit-db. Hope you will enjoy!!!