Is your birth date important if you are a hockey player? Do you know that 70% of NHL hockey players were born in the first three months of the year? The book "Outliers" (see http://www.gladwell.com/outliers/index.html ) talks about how certain things besides talent determine success.
Apparently to really make it big in the computer business being born between 1952 and 1958 was really important. It was the beginning of online computing as opposed to using punched cards or paper tape. I got into the business when cards and paper tape were the rage. Gates, Job, and the founders of Sun Microsystems were all born in that period.
The idea is that certain things about dates can really make a difference. In hockey the age group you played in was determined by your age on December 31st. So people who were born in January played with people who could be up to a year younger. They were bigger and thus played better generally. Then as they got older they were still the bigger boys on the teams. When rep teams were picked they were more likely picked. They then got better coaching and played more. Those things lead to even greater success. Isn't that fascinating. Hockey players born in the first three months of the year become outliers.
Apparently there was a study identifying the seventy-five riches people of all time and fourteen of these people were US citizens and were born in a twenty year period. They include Rockefeller, Carnegie, and those tycoons of the early industrial age in the US. They were all born in the early 1800's and were at the right stage in their career to take advantage of a great opportunity. This group become Outliers because of when they were born.
The book is a study of things beyond the obvious that differentiate people.