I started "working" a few hours a week teaching programming at my kids' school. When they put me on the payroll I was astounded by the number of forms I had to fill out. I counted 15 forms requiring my signature, no less than 5 of which required my SSN. Lo and behold, there was a data breach of employee and volunteer records. Volunteers had to have background checks, which required the SSN. Thousands of people had th…
You can look at it from the other side too, maybe Americans are putting too much weight on the SSN. I could practically post my Spanish ID number next to my name online and nothing would probably happen. As a matter of fact, a stupid regional government agency posted it next to my name in 2011 and it's been up ever since.
It just that most people believe that not making their SSN public is enough for it to be safe.