What if their surname was 'Smith'? Try typing that into Google and see what results you get - I bet none are related to the person you are trying to look up. Try 'Robbie Williams' or 'Brad Pitt' on the other hand....
It does work, but you get a list of all the people with your name so you have to type in as full a name as possible and then sort out which one you want to know about. My real name is not a common one but there are quite a few mentions of the name on the web and not all of them are me!
As woogang says, it does work, we have some relations in Australia that we didn't knoe existed, my nephew did a search using this method, and we now have an extended family, but we do have a surname thats not too common.
Apart from one famous author and a former US senatorial communications director, my surname is quite uncommon. However, I did enter my full name and found that I share it with a priest who lived in Dhaka in the 1930's.
I found me......at least it was my name and everything in the newspaper article could have been me but it most definitely was not the real me! Very strange.