Duplicate names

Years ago, I read in some forgotten reference volume in the campus library, that my family name "Kirby" was the 511th most common last name in the US.  Today, I saw similar figures, in the 500's.  This subject came up in articles about the Tyler Perry movie "The 6 Triple 8" about difficulties in getting news to and from US soldiers in Europe during WWII.  The 6888 Battalion of Black US women soldiers were given the task of sorting 17 million pieces of backed-up mail to US troops and their loved ones at home.

The white, disdainful general visits their operation and is told about the problems the hard-working women encounter: poor, indecipherable writing; incomplete addresses and what is now called Googlegangers (different people with the same name).  I read the other day that 7,500 US soldiers were all named "John Smith"! 

I have had the experience of dealing with an official who clearly uses my ZIP code, birthdate, and other characteristics to identify me.